Electrical Woes - need direction

[TEXAS 57]

Hello. Sorry, this may get lengthy.

I recently purchased a 99 LX470. It had some headlight issues that I thought I could clear up pretty easy. I am in Houston, TX so I thought the truck may have been a flood car but after a good rain, I think it just had a bad installation of the windshield as after the last rain the driver side kick panel carpet was soaked.
The instrument cluster was swapped recently before I took possession and everything there works fine. I do not know why it was swapped.

Here are the issues:

AC issues:
AC and heat work as they should but the buttons seem like they intermittently work. The large auto button doesn’t work at all. The Recirculating and AC button take a couple of presses to work.

Seat memory does not work. Seat motors function great.

Telescoping wheel does not work. Tilt does work.

Headlight issues:
DRLs work fine
Parking lights work fine but turns off AC and radio lights on center dash. Gage cluster lights work fine.
Switch to HL on the brights come on. Center dash lights come on.
Switch to auto the brights come on. Center dash lights stay on.
Brights will not turn off with dimmer switch but do flicker.
Switch back to off and nothing happens. I have to disconnect the battery to turn the lights off.
I can hear the DRL relay click off on the Pass side behind Headlight.

AHC does not work.
It is on Normal. Does not go up or down. Push button to low - Flashes Low but doesn’t move. High does nothing. I can turn it off. The ride comfort selector works fine. I do not think this is related but started a separate thread here AHC Issue... Not working at all

So I got the Diagking Mini VCI cable from Amazon. https://www.amazon.com/gp/product/B07BCNPDDG/ref=ppx_od_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I have a 2002 TLC and a 1997 4Runner. Plugging into both of those produces great results. Everything reads and the health check is fine.

When I plug into the LX, it reads it as a 1998 Land Cruiser (has the ECU been changed?).

When running Health check:

Engine and ECT is fine

Cruise Control is fine

AHC - no pressures / can’t do active tests / no DTCs / see pic

ABS VSC TRAC:

C1241 low battery positive Voltage or abnormally high positive Voltage
(Leads me to believe there is something wrong with the Alternator)

Body ECU:
B1213 tilt and telescope ECU communication stop

B1215 door system communication bus (GND short) (maybe I had the door open... can’t remember)

Immobiliser is fine

SRS airbag is fine

Driver seat ECU - crashes program

Tilt and tele ECU - Not responding or not available

Mirror ECU - Not resp or not avail


On the headlight issue- I have switched all the relays with working ones from the Land Cruiser (DRL3, HEAD relay, DIMMER relay, and the MAIN DRL relay) and nothing changed. I think the only thing left is the Switch and ECU from the EWD.

I think the AHC is a separate issue.
I think that water dripping in from the windshield has damaged some electronics.

Just not sure where to go from here and looking for some more experienced guidance.

 

[ZetheGSD]

OK OK... This is a large amount of diagnosis that it seems you have taken a fair bit of time to try and wrap your head around. Sounds like you need to step back and reassess what could cause multiple issues and potentially cause all of your concerns. I believe that there is a large junction box as well as the interior fuse box all located in the drivers side kick panel. If I were you I would probably roll the dash and look for water damage first, then pull these large electrical components and look inside them for corrosion. Sounds like the previous owner has taken a few swings at fixing this truck with little success. I'm almost willing to bet you will find the root of your issues inside the housings of these components. But take a look as best as you can and report back!

 

[PADDO]

Quite a laundry list of problems, as an EE who doesn’t enjoy Auto electrics I wish you good luck with it all! The FSMs and EWD will be invaluable. Can you put a portable dehumidifier in the truck and start the drying process?

For your AHC you are showing 1.7v in th B+ field and it should be 13ish volts (from main battery dist. system) so check you 15A AHC B fuse and the AHC main relay. Ain’t nothing going to happen AHC/AVS wise if the ECU isn’t getting proper power.
Tilt and telescope steering column motor failure is very common so you may not have a ECU control problem there.

 

[Qtonic]

When I plug into the LX, it reads it as a 1998 Land Cruiser (has the ECU been changed?).

That's normal on a 98 LX. You have to manually change it. Possible the 99 LX also doesn't register normally.

As for the crashes or other problems when accessing certain modules, manually identifying the year and model will likely help that to some degree (if you didn't already), but occasionally I still experience that on the 98. I just work around it. Sometimes a second try works. I doubt that's a sign of a problem, just techstream bugs that, in my experience, seem to be more common on the early models.

One thing I didn't realize before getting the 98 is that there are fewer techstream options than my 07, such as door lock beep and other functions/utilities, that have screens but no choices once accessed.

 

[Ninja Cruiser100]

I would strongly agree with Paddo that recommended putting a portable dehumidifier in your car. Is it garaged?

If there is a leak this should stop it long enough to identify the cause. The damage may be harder to diagnose.

 

[TEXAS 57]

I do have a dehumidifier and some Damp Rids in the truck now and they are pulling water. I have also pulled the windshield trim and am cleaning the area up and going to put it back nicely. It was really shotty work. The LX sits outside... The 57 stays indoors with all the tools.

Quite a laundry list of problems, as an EE who doesn’t enjoy Auto electrics I wish you good luck with it all! The FSMs and EWD will be invaluable. Can you put a portable dehumidifier in the truck and start the drying process?

For your AHC you are showing 1.7v in th B+ field and it should be 13ish volts (from main battery dist. system) so check you 15A AHC B fuse and the AHC main relay. Ain’t nothing going to happen AHC/AVS wise if the ECU isn’t getting proper power.
Tilt and telescope steering column motor failure is very common so you may not have a ECU control problem there.

Thanks for the tips. I was hoping you would chime in after reading many of your posts. I have not started to diagnose the AHC yet as I think it is separate. I will check the Fuse and Relay and report back.

That's normal on a 98 LX. You have to manually change it. Possible the 99 LX also doesn't register normally.

As for the crashes or other problems when accessing certain modules, manually identifying the year and model will likely help that to some degree (if you didn't already), but occasionally I still experience that on the 98. I just work around it. Sometimes a second try works. I doubt that's a sign of a problem, just techstream bugs that, in my experience, seem to be more common on the early models.

One thing I didn't realize before getting the 98 is that there are fewer techstream options than my 07, such as door lock beep and other functions/utilities, that have screens but no choices once accessed.

I have been manually entering in the info. Glad to hear that LXs read as a Land Cruiser. I was afraid a Land Cruiser ECU may not have all the function of the LX (and could be causing issues.) I wish it was as easy as swapping the ECU though.

I see no options on any of my trucks to customize.

 

[kruisinkid]

If you dont already you must get a paper copy of the EWD specific for your year and model. The differences are vast between toyo and lx and then change frequently as the years increase. The one lumped in with the 04 FSM floating around is probably very little help. You should at the very least silicone all the roof rack bolts and add contact cement under all the windshiled mouldings yiu can easily get to, or better yet go have your glass pulled and replaced with OEM mouldings. Best of luck

 

[TEXAS 57]

Alright. Sorry it has been a while but I’ve got three kids and a busy schedule.

I dried the truck out with a dehumidifier for a couple days and stuck some DampRids in there.

I pulled the windshield trims and found gobs of adhesive under the trim on the roof so I cleaned all that out. The trims were screwed in , not rivited. I will correct all this.

I have not been able to recreate a leak even by spraying the water hose directly into the seams. I sprayed the roof rack too. I still want to pull the roof rack to clean it up and will make sure it is all sealed up then.

I pulled the dash to look for signs of water intrusion, rust or corroded connections. I found none. This is good because I thought it was a flood vehicle but if it was, it did not get the interior connections wet.

There is Zero rust around the windshield on the inside or outside.
This was the most I found:

I have an 02 LC Wiring Diagram but went ahead and got the 99 LX Wiring Diagram too.

The headlight diagrams are similar.

The only thing I have not switched out is the actual switch stalk and the instrument ECU. (Recall I think my Instrument Cluster was switched at some point because the mileage was off from the CarFax.)

I cleaned every ground found in the wiring diagram with a wire brush and applied dielectric grease.

Quite a laundry list of problems, as an EE who doesn’t enjoy Auto electrics I wish you good luck with it all! The FSMs and EWD will be invaluable. Can you put a portable dehumidifier in the truck and start the drying process?

For your AHC you are showing 1.7v in th B+ field and it should be 13ish volts (from main battery dist. system) so check you 15A AHC B fuse and the AHC main relay. Ain’t nothing going to happen AHC/AVS wise if the ECU isn’t getting proper power.
Tilt and telescope steering column motor failure is very common so you may not have a ECU control problem there.

Thanks Paddo! One step closer! I checked all connections to the AHC ECU and they look great. The 15A B fuse was blown. I replaced it and worked the switch. It took a bit but it did lower. I could not make it go back up with the switch.

I went ahead and pulled every fuse and relay one by one in the engine compartment and interior panel to check them.

 

[TEXAS 57]

Today I swapped out the headlight switch stalk with a known working one but that made no difference.
I also swapped all of the relays from a working vehicle and the headlight issues did not change.
The only element left is the Instrument ECU. The 2002 LC’s part # is different so I will not be able to swap that. I may have to buy one.

 

[TEXAS 57]

I have been unable to reproduce the leak. I did find an old piece of windshield goopthat was hanging across the door weatherstrip so I think that is where my leak came from. That’s good and bad... good because I don’t have a leak... bad because I still do not know where my electrical woes are coming from.

I was able to use Techstream and got these readings. I used the utility tool and was able hear every solenoid and relay fire.

Looks like I have good voltage to the system now. I still could not get it to rise up in the driveway.

 

[TEXAS 57]

SOLVED! But not sure how... I am thinking it was a bad contact from the signal of the switch to the relay.

The only thing that changed is I replaced this telescoping bushing and noticed a metal grounding tab in the bushing. The bushing was beat up pretty bad so maybe there was no contact.

Time to put it all back together...