AC Inoperable, collective wisdom of mud help (1 Viewer)

[2001LC]

So a local mud member (a mechanic) brought me his clean 04LC w/157K miles, for diagnostic of inoperable AC. He had it at Toyota Dealership which told him to start by replace AMP ((NAV unit). He declined as he's done that! In researching Toyota Service History, he found PO had it in Toyota Dealerships also for same. They also replace the AMP. Also note the OAT (outside air temp) read out is reading ---. The OAT sensor has been replaced.

Here's a picture on cold engine start up. The air blow out vents hot, once engine hot. Make no difference if set to hot cold or in-between.

I did hook my code reader (Blue Tooth, read on iphone). I saw a few unrelated DTC dealing with CDL, but no DTC for AC. Could be my reader or code may have been cleared. I've not yet hooked up to tech stream with mini VCI.

I was given a write account of what been going on and done. These are presumable DTC that have come up:

1. I was told Toyota Dealerships checked, and say the system is fully charged.
2. I noticed wire protective sheathing on compressor was split and wire separated. Like as if someone connected to them with test (OMS, AMP, Volts) equipment. I tested magnetic clutch by jumping with + from battery. Clutch tested good. I tested OMS of lock on clutch they tested ed at 800 OMS which is within speck.

Also worth note:

1. In speaking with owner, he said he did have open holes in "A" pillar from bad windshield install job. He has corrected.
2. I can hear the heater relay "click" as I turn AC on and off (HVAC auto ANd FAN), so getting or drawing current from main relay (or so clicking sound indicates). AC compressor clutch does not ever engage even for defrost.
3. No signs of rodent chewing wires.
4. I've not checked and not sure how? if I can't get compressor clutch to lock.
5. I did not check pressure switch for same reason and because off road bumper blocking (for now)
6. I pulled lids off all fuse boxes. In the RH foot well junction box. I found the RR A/C fuse was stuck in slot. In pulling it and fuses next to it, they were all stuck. They all had what looked like some (small amounts) white corrosion on them. The LH junction box nor fuse box under hood had any stuck or white corrosion. The main fuse box under the hood did have and accesses hole cut into it's side.
   

Thoughts:
Water entry cause some damage to junction box or computer nearby in LH foot wheel or somewhere. This is where water entry issues typical cause an audible brake alarm, that go away once dry. This may have caused a short, that is keeping OAT from displaying, AC compressor and servos from working????


Any help any thoughts are appreciated????????????????????????????????????? HELP!.

 

[2020 Rocks]

If the sunroof drains are clogged you can get water in that area, or if the rocker panel drain is clogged, the water will back up into that area. I recently added a trailer brake controller and came across water issues. Drained the rocker plug, cleared the sunroof drain, and it is now dry. I had a friend who had a lexus RX300, his Nav panel went out and so did heat and ac along with it. He ended up getting a used but working Nav panel off ebay to swap out with the bad one. I can't remember exactly what Lexus wanted for a new panel but it was a few grand. The used ebay one he bought was around 800 if I remember correctly.

 

[hickuptruck]

X2. I'd start with water intrusion stuff. Every 100 series has a boat load of grime and dirt and leaves right where the front fender drain is, behind the plastic fender guard. I pulled out 3 handfuls of rotting crap on mine.

 

[2001LC]

My Issues at this moment, is reading the wiring diagrams, which is not my strong suite. I can not find the affected system within EWD. Need some help with this first thing?

If the sunroof drains are clogged you can get water in that area, or if the rocker panel drain is clogged, the water will back up into that area. I recently added a trailer brake controller and came across water issues. Drained the rocker plug, cleared the sunroof drain, and it is now dry. I had a friend who had a lexus RX300, his Nav panel went out and so did heat and ac along with it. He ended up getting a used but working Nav panel off ebay to swap out with the bad one. I can't remember exactly what Lexus wanted for a new panel but it was a few grand. The used ebay one he bought was around 800 if I remember correctly.

X2. I'd start with water intrusion stuff. Every 100 series has a boat load of grime and dirt and leaves right where the front fender drain is, behind the plastic fender guard. I pulled out 3 handfuls of rotting crap on mine.

Thank you both for the input. Where I do suspect water entry at one point, it is dry now. The Toyota Dealership and the Owner (mechanic) both replaced the NAV (AMP as they called it), in fact one was left in back seat for me, if I'd like to try. But these replacements have done nothing to correct issues.

No CEL is present nor has one been ever been reported on this/these issues to my knowledge. This may also be a clue!

I've seen a few times where RH side junction box created brake alarm issue. In where no CEL ever came on;

These sometimes went away when dried out for few days and no car washing, rain or snow.​

These were water entry from bad windshield job. Water ran down "A" pillar into electronics. This 04LC had open holes in "A" pillar from bad windshield install job. Those have been corrected. Everything is dry.​

​

Other times the RH junction box(s) have needed replacing. In these cases there was no known water entry and nothing done to seal up or clear/close possible water entry issue ever reported. Solution was to just replaced the RH junction box. Seems there was a TSB on this one issue around 2003.​

​

In both those above, brake alarm would sound when e-brake on. No CEL!​

​

I suspect that if I can find convergence of all affected systems. i.e. OAT read out, AC compressor and servos for dampeners in HVAC. Then I'll have a good point to try solution on. Possibly HVAC control assembly, junction box or CPU, or combination of them!

I'll repeat to stress my plea for this moments help I'm looking for:
My Issues at this moment, is read the wiring diagrams, which is not my strong suite. I can not find the affected system within EWD. Need some help with this first thing?

Second would be: how do I test that A/C system is indeed fully charge and pressure switch is working. With an inoperable compressor?

 

[2020 Rocks]

You might get lucky, or you may have hours of testing things ahead of you. You will need to check all of the circuits for continuity and slowly by process of elimination find out where the gremlin resides. If you had a donor rig, some of the things you highlighted above could possibly swapped and tested, but after repeated water entry in the past and Nav panel issues, I suspect trouble shooting this will take some time. I think based on the electrolysis you described, I would pull all fuses, maybe replace them all as theyre not that costly, and clean up all of the contacts on the panel. Next I would focus on where the water entered in the past, focus on possible routes it may have taken once past the firewall to see if it leads to other things that could have also been damaged but remain as of yet unseen. I wish you luck, I hate electric gremlins. I've gotten lucky in the past and also had to throw in the towel more that a few times.

 

[2020 Rocks]

Some other things, check the pressure at both the high and low side. Just because they said it was checked, I would double check it to be sure to properly eliminate possible issues. Check the low and high side pressure lines. An overfilled AC system will cause the system to not work and could possible cause other issues. The low side should be around 30 psi I believe, anything 40 or above would be of concern.

 

[gatormark91]

My Issues at this moment, is read the wiring diagrams, which is not my strong suite. I can not find the affected system within EWD. Need some help with this first thing?



Thank you both for the input. Where I do suspect water entry at one point, it is dry now. The Toyota Dealership and the Owner (mechanic) both replaced the NAV (AMP as they called it), in fact one was left in back seat for me, if I'd like to try. But these replacements have done nothing to correct issues.

No CEL is present nor has one been ever been reported on this/these issues to my knowledge. This may also be a clue!

I've seen a few times where RH side junction box created brake alarm issue. In where no CEL ever came on;

These sometimes went away when dried out for few days and no car washing, rain or snow.​

These were water entry from bad windshield job. Water ran down "A" pillar into electronics. This 04LXC had open holes in "A" pillar from bad windshield instill job. Those have been corrected. Everything is dry.​

​

Other times the RH junction box(s) have needed replacing. In these cases there was no known water entry and nothing done to seal up or clear/close possible water entry issue ever reported. Solution was to just replaced the RH junction box. Seems there was a TSB on this one issue around 2003.​

​

In both those above, brake alarm would sound when e-brake on. No CEL!​

​

I suspect that if I can find convergence of all affected systems. i.e. OAT read out, AC compressor and servos for dampeners in HVAC. Then I'll have a good point to try solution on. Possibly HVAC control assembly, junction box or CPU, or combination of them!

I'll repeat to stress my plea for this moments help I'm looking for:
My Issues at this moment, is read the wiring diagrams, which is not my strong suite. I can not find the affected system within EWD. Need some help with this first thing?

Second would be: how do I test that A/C system is indeed fully charge and pressure switch is working. With an inoperable compressor?

If you jump the clutch with a wire that won't get ripped off by the serp belt, you should feel the hard line coming out of the evap core getting colder. Then check the pressure. Not much you can check without the compressor turning.

Apologies if you did this already and I missed it in the above notes.

 

[flintknapper]

@ 2001LC you can check the 'static' pressure of the system by hooking up your gauges (engine off, AC off) high and low side valves closed.

Be sure and take an ambient temperature reading right before you do this (about 1 foot in front of the condenser). The pressure reading should be roughly equal on both gauges. According to what you come back with....we can tell IF the system has enough liquid refrigerant and pressure to satisfy the low pressure portion of the binary switch. It will NOT (can not) tell us how much refrigerant is in the system and unless the dealer evacuated the system and weighed it....then they don't know either.

Once we've determined there is enough pressure to allow the clutch to work...we can move on to the next set of tests. Or mark off the ones you might have already done. I'm right in the middle of packing up my Daughter's truck right now...for her trip to Denver, so I will check back later.

Let me know what your static pressures are...and I can tell you if they are correct for the ambient (and your approx. altitude).

 

[Mike6158]

Normal running pressures from the service manual:

 

[white_lx]

Looking at all error codes from your notes, the sensors and the listed dampers share one thing: the FRSG pin of the A/C control assembly. FRSG probably means FRont Signal Ground. (front for 'front A/C'). These are the Yellow-Green wires that are all connected between the sensors grounds and damper position pot grounds and then connect back to the FRSG pin on the A/C control assembly.

See the attached relevant page from the wiring diagram. Interesting part is that junction box 3 (greyed out area of the FRSG signal junctions starting with a '3') is located behind the right kick panel. Is that where you observed the water / corrosion?

I would start with the simple problem: there is no outside temperature signal.

Measure the voltages to chassis ground at the outside temperature sensor connector in the front of the vehicle. One leg should be connected to the FRSG which is probably '0V' and the other one should have some voltage (not specified in the FSM), but I assume ~ 3-10V with the sensor in place. I would measure this key-on as this would also show any bad connections which a resistance measurement would not show.

Apparently diagnostics page DI-1319 has some more information about testing the outside temperature signal circuit, but I was unable to find that FSM page online.

 

[2001LC]

You might get lucky, or you may have hours of testing things ahead of you. You will need to check all of the circuits for continuity and slowly by process of elimination find out where the gremlin resides. If you had a donor rig, some of the things you highlighted above could possibly swapped and tested, but after repeated water entry in the past and Nav panel issues, I suspect trouble shooting this will take some time. I think based on the electrolysis you described, I would pull all fuses, maybe replace them all as theyre not that costly, and clean up all of the contacts on the panel. Next I would focus on where the water entered in the past, focus on possible routes it may have taken once past the firewall to see if it leads to other things that could have also been damaged but remain as of yet unseen. I wish you luck, I hate electric gremlins. I've gotten lucky in the past and also had to throw in the towel more that a few times.

At this point I hope to not do the very timely one by one test. I feel many shops/tech took this approached and failed to see what I think may be what caused issues "water". It is good advise so thank you. I do have a few rigs I'm not driving at the moment. I'd need to cross check parts. Then hope issue doesn't short my parts. It is on the table, so we're thinking along same lines. Thanks!

Some other things, check the pressure at both the high and low side. Just because they said it was checked, I would double check it to be sure to properly eliminate possible issues. Check the low and high side pressure lines. An overfilled AC system will cause the system to not work and could possible cause other issues. The low side should be around 30 psi I believe, anything 40 or above would be of concern.

If you jump the clutch with a wire that won't get ripped off by the serp belt, you should feel the hard line coming out of the evap core getting colder. Then check the pressure. Not much you can check without the compressor turning.

Apologies if you did this already and I missed it in the above notes.

I've not tried and will keep in mind. Thanks.

Normal running pressures from the service manual:

Handy when I get compressor running.

@ 2001LC you can check the 'static' pressure of the system by hooking up your gauges (engine off, AC off) high and low side valves closed.

Be sure and take an ambient temperature reading right before you do this (about 1 foot in front of the condenser). The pressure reading should be roughly equal on both gauges. According to what you come back with....we can tell IF the system has enough liquid refrigerant and pressure to satisfy the low pressure portion of the binary switch. It will NOT (can not) tell us how much refrigerant is in the system and unless the dealer evacuated the system and weighed it....then they don't know either.

Once we've determined there is enough pressure to allow the clutch to work...we can move on to the next set of tests. Or mark off the ones you might have already done. I'm right in the middle of packing up my Daughter's truck right now...for her trip to Denver, so I will check back later.

Let me know what your static pressures are...and I can tell you if they are correct for the ambient (and your approx. altitude).

Looking at all error codes from your sheet, the sensors and the listed dampers share one thing: the FRSG pin of the A/C control assembly. FRSG probably means FRont Signal Ground. (front for 'front A/C'). These are the Yellow-Green wires that are all connected between the sensors and the dampers and then feed back to the FRSG pin on the A/C control assembly.

See the attached relevant page from the wiring diagram. Interesting part is that junction box 3 (greyed out area of the FRSG signal junctions starting with a '3') is located behind the right kick panel. Is that where you observed the water / corrosion?

I would start with the simple problem: there is no outside temperature signal.

Measure the voltages to chassis ground at the outside temperature sensor connector in the front of the vehicle. One leg should be connected to the FRSG which is probably '0V' and the other one should have some voltage (not specified in the FSM), but I assume ~ 3-10V with the sensor in place. I would measure this key-on as this would also show any bad connections which a resistance measurement would not show.

Apparently diagnostics page DI-1319 has some more information about testing the outside temperature signal circuit, but I was unable to find that FSM page online.

@flintknapper & @white_lx I was really hoping you both were around and chimed in. Thank you. You both always give great actionable AC info.

I'll go over all your recommendations and get too, then post ASAP. But that may take awhile.

"located behind the right kick panel. Is that where you observed the water / corrosion?" YES! This is good news. I feel I'm on right track, with your findings giving me confidence.

 

[2001LC]

BTW @flintknapper PM me and I'll give my contact info to use, If your daughter needs anything while here in Denver.

 

[Njck22]

Looking at all error codes from your notes, the sensors and the listed dampers share one thing: the FRSG pin of the A/C control assembly. FRSG probably means FRont Signal Ground. (front for 'front A/C'). These are the Yellow-Green wires that are all connected between the sensors grounds and damper position pot grounds and then connect back to the FRSG pin on the A/C control assembly.

See the attached relevant page from the wiring diagram. Interesting part is that junction box 3 (greyed out area of the FRSG signal junctions starting with a '3') is located behind the right kick panel. Is that where you observed the water / corrosion?

I would start with the simple problem: there is no outside temperature signal.

Measure the voltages to chassis ground at the outside temperature sensor connector in the front of the vehicle. One leg should be connected to the FRSG which is probably '0V' and the other one should have some voltage (not specified in the FSM), but I assume ~ 3-10V with the sensor in place. I would measure this key-on as this would also show any bad connections which a resistance measurement would not show.

Apparently diagnostics page DI-1319 has some more information about testing the outside temperature signal circuit, but I was unable to find that FSM page online.

I agree with your conclusion. I would check for continuity between those wires coming in and out of the RH junction box at their respective pins. This is the solution that would connect all the dots. The AC Magnetic clutch is controlled by the ECM, going off signals from the AC Amplifier.
Check for continuity between the male pins/terminals 1,2,3, and 13 on the Junction box.

its the middle of the three connectors coming from what seems the top or one of the sides of the box.

internal

 

[2001LC]

I agree with your conclusion. I would check for continuity between those wires coming in and out of the RH junction box at their respective pins. This is the solution that would connect all the dots. The AC Magnetic clutch is controlled by the ECM, going off signals from the AC Amplifier.
Check for continuity between the male pins/terminals 1,2,3, and 13 on the Junction box.

its the middle of the three connectors coming from what seems the top or one of the sides of the box.

internal

Not sure which three wire harness blocks those are.

Above the wire blocks with some grease on wires. I see what may be the "3" WIRE blocks, like in the diagram. Seen above (to upper right of picture) the greasy wires, which is top of fuse junction box?

Grease! Someone was in here at some time or something splashed up RH foot-well that looks like dielectric

 

[flintknapper]

Not sure which three wire harness blocks those are.
View attachment 2028310
Above the wire blocks with some grease on wires. I see what may be the "3" WIRE blocks, like in the diagram. Seen above (to upper right of picture) the greasy wires, which is top of fuse junction box?
View attachment 2028311
Grease! Someone was in here at some time or something splashed up RH foot-well that looks like dielectric
View attachment 2028312

All that grease needs to come out of there.
A combination of compressed air and then electrical contact cleaner should do it. It's going to be messy, but you already know that.

Dielectric grease is an insulator and while it does a good job of preventing corrosion, IF any of the connections are loose (unable to displace the grease and make good contact) it can prevent current flow.

 

[Njck22]

Not sure which three wire harness blocks those are.



Grease! Someone was in here at some time or something splashed up RH foot-well that looks like dielectric

The connector that has the sensor ground is unfortunately located on the back of that junction box. but you'll probably have a bit of stuff already out to clean some of that grease out.

on the subject of the dielectric: I don't think that grease is the problem. Toyota even uses it under the seats from what I remember and that never seems to cause an issue. Toyota terminals make a considerably strong mechanical connection.

 

[flintknapper]

on the subject of the dielectric: I don't think that grease is the problem. Toyota even uses it under the seats from what I remember and that never seems to cause an issue. Toyota terminals make a considerably strong mechanical connection.

^^^^

Agree....I don't think that is going to be his problem. But it looks like someone just slathered a bunch of grease in there sometime in the past. For what reason? I would wager corrosion and we can't see corrosion/other until we get that grease out of there.

Typically, Toyota connections are indeed reliable...BUT if someone has been in there monkeying around...we have no idea the condition, hence my advice to start 'clean' and inspect.

I'm confident...with the collective knowledge here and @2001LC's abilities (he is meticulous) it will get sorted out.

 

[jerryb]

Paul, your pic shows you with a setting of max cool. IN that instance don't forget that all the temp signals are ignored and it wouldn't matter if they worked or not. The AC should still work.

getting all those AC diagnostic codes in one trip through the AC diagnostic phase I'd assume it's a single point issue at the front end like water or a fuse, mag clutch, main fuse box etc.
I use techstream to activate the mag clutch, if you can do that and observe pressures at the same time you should be able to verify that activation is ok. It's unclear if you got the compressor to work with just the buttons in the car. RPM rise when you hit the AC button is a givaway

2004 is an odd year. Don't use any 2005-7, or lower than late 2003 parts like fuse boxes, ac amps, etc. The wiring is different, compressor control being one thing.

 

[white_lx]

Did a little bit more research. It seems that Toyota uses a 5V reference circuit for sensors for many of its vehicles (like many other manufacturers). Not sure if that also applies to the LC platform, but it probably is a good guess.

That means that you should read +5V between the pins of outside air temperature sensors with the sensor unplugged. Maybe also when plugged in, but that is difficult to know without knowing the circuit diagram of the A/C control system.

Verifying the +5V would be a quick way to see if the A/C control amplifier is at least up and running.

This is worth watching, for those of you who want to know more about sensor grounds and reference voltages:

 

[2001LC]

Today I'll hook up my manifold to see static pressures (first thing). Then I'm going to see what it takes to pull the RH junction block. I need to see if I can find more signs of corrosion. I'll clean up the grease and what else I find that needs cleaning while in there. But it may just need replacing. It would be great if this the issue.

@jerryb The compressor does not engage the magnetic clutch in AC, defrost, heat or in any temp setting. I've not tried hooking up or going through tech stream "yet". Good idea! Thanks. But will have to wait until later: I put a ceiling with solar barrier and ~R40 insulation in my garage last winter, so stays cool (75 to 80F when OAT 95F) in shop. But have yet to install a window AC, insulated doors or walls. So for now, it just to hot outside to open doors (stays cooler closed up), run engine or even bring in a cruiser that been in the sun. Just gets to hot to work comfortably. So maybe late in the evening when it cools down, I'll run tech steam.

The only 100 series I've here 00LX, 06LC and 07LX that I could have pulled from. But if I need to stick with 03-04, I'm shot down. I keep all parts rig in area on a list, none in that year are around. I would have thought I could go up to May 05. I hate to buy a RH junction block just to test, but I may.

@white_lx I'll need to get better understanding of where to test circuit of OAT sensor. The owner said it is a working replacement sensor, so for now I'll assume is. So somewhere between sensor and display input is shorted. I've suspected all along, it is all related to the same issue.

Is the AC Amplifier in the NAV unit?
If so, I can safely assume "for now" that it's working fine. As it been replaced twice. That is, provide it's not being damaged by short elsewhere each time a replacement was installed.

This thread has really come up with some good stuff. Thank you all so much. Keep it coming.