Problem with blower/fan intermitenly working (1 Viewer)

[outdoort]

Hey fellas, I've had a persistent problem for the last few months that I've put off diving into. My blower/fan for the AC/heater only intermitenly works. Over the summer it has seemed to randomly either work or not work (on every power setting including High, both heat and ac). I might press the button and it works for a while while driving then if I stop and shut off the ignition, then put the key back in and turn the vehicle on, and the blower doesn't work.
Now that the temp. here in PA. is getting cold (espesially in the morning, mid 20s) I need this to work for me so I can use my defrosters. What I have noticed lately is that it seems to work when the engine is cold-thank god every morning when I wake up for work the blower works Then I'll drive 15 miles to starbucks, get my coffee, then get back in my 80, and the blower/heat doesn't turn on. Also, when I park my 80 at work or at home for the night I have made sure one of the blower settings is turned on (when the blower isn't working, like it should). Then several hours later when the car is completely cooled down, I'll put the key in the ignition, turn the key to "on" and bam: blower turns right on (because I left it on low, med., high setting)
So the blower seems to shut off when the engine is warm/hot, but never has shut off on me while I've had it turned on. It always happens when I either turn the 80 off, or turn off the blower, then try to turn it back on.
I hope my explanation has made sense to you all, and I've included helpful info. I have done a search on this and I really havn't turned up anything. Thanks for everyones help, I have the weekend off and I plan to try and work on this and fix the problem.

 

[outdoort]

So no one has any leads on this one?

 

[none]

I'd wager the control head is s***ting on you. If you want to eliminate it, pm me and i'll send you my old head unit. The heat/cool slide doesn't work, but the fan speeds and mixer buttons work properly. I replaced it a few weeks ago with a good used unit.

 

[outdoort]

I'd wager the control head is ****ting on you. If you want to eliminate it, pm me and i'll send you my old head unit. The heat/cool slide doesn't work, but the fan speeds and mixer buttons work properly. I replaced it a few weeks ago with a good used unit.

The control head? Do you by chance know what specifically its called so I can look this up in the service manual. Thanks.

 

[djzimms]

It's been a looooong time, but, I have the same exact issue. Do you recall what you did to fix this issue?

 

[Tools R Us]

If it just the blower that doesn't work, start by checking the relay. In some cases, cleaning the contacts works.

 

[djzimms]

I was checking for the relay from the diagram listed in the thread. Not sure I have the best service manual as it's the Haynes repair manual. I have a LX450, and from the diagrams in my service manual, it seems like the relays may be different?

 

[djzimms]

Trying to locate to do just as you stated as described in this post.

 

[djzimms]

BTW, I know we chatted before, if you can't tell from my profile pic, I got the axles swapped out and an Old Man Emu lift installed from the botched lift.

 

[djzimms]

People with a similar issue posted this thread as a potential fix, what do you think about this? 97 LC Collectors Edition Climate Control

I found the option circuit board for around $130 online. That is, if cleaning the relays doesn't work.

 

[fitzonthemark]

I would wager it is the blower resistor. There is a thread about it with this handy photo.

Blower Resistor Location '94 FZJ80

 

[djzimms]

Okay. Well, that's what the auto shop near me thought too. They pulled it out and tested it though and according to them, they thought it was performing within appropriate parameters (after they told me that's what it was and I bought the part). It's being delivered ground, so I'll have that this coming week and can test it out. I also bought some electrical cleaner that'll be here tomorrow night from Amazon. So, I'll trying cleaning up the amp cooler component as well and test to see if that helps. There's literally one pin that's corroded, but, I suppose that could do it. Another area seems okay, but does seem to have very very light corrosion.

 

[Tools R Us]

The blower resister only comes into play at lower speeds, so if high speed doesn't work, it's not the problem. What works, what doesn't, does the switch panel light up, the A/C button light when pressed, no blower speeds work? FSM available here:

For Sale - 40, 50, 60, and 80 series FSM for a hell of a price.

Both sides of the blower, power and ground are switched, so the problem could be in either side. Set the blower to max, key turned to run, unplug the blower, test the connections, does it have power and ground, if not which one is missing? This cuts the search in half, the problem is on that side of the circuit. Most times, not always, if none of the blower speeds work and everything else works, the problem is on the power side.

1. HEATER BLOWER MOTOR OPERATION
CURRENT IS APPLIED AT ALL TIMES THROUGH THE FL HEATER FUSE TO TERMINAL 5 OF THE HEATER RELAY. WHEN THE IGNITION
SW IS TURNED ON, CURRENT FLOWS THROUGH THE GAUGE FUSE TO TERMINAL 3 OF THE HEATER RELAY → TERMINAL 1 →
TERMINAL HR OF THE A/C AUTOMATIC AMPLIFIER. AT THE SAME TIME, CURRENT ALSO FLOWS FROM THE GAUGE FUSE TO
TERMINAL IG OF THE A/C AUTOMATIC AMPLIFIER AND TERMINAL 4 OF THE BLOWER HI RELAY → TERMINAL 3 → TERMINAL FR OF
THE A/C AUTOMATIC AMPLIFIER AND TERMINAL (B) 13 OF THE BLOWER SW.
(LOW SPEED OPERATION)
WHEN THE BLOWER SW IS PUSHED TO LO POSITION, THE CURRENT TO TERMINAL HR OF THE A/C AUTOMATIC AMPLIFIER FLOWS
TO TERMINAL GND OF THE A/C AUTOMATIC AMPLIFIER → GROUND AND TURNS THE HEATER RELAY ON. AS A RESULT, THE
CURRENT TO TERMINAL 5 OF THE HEATER RELAY FLOWS TO TERMINAL 4 → TERMINAL 1 OF THE BLOWER MOTOR → TERMINAL 2
→ TERMINAL 1 OF THE A/C POWER TRANSISTOR → TERMINAL 2 → GROUND AND CAUSES THE BLOWER MOTORS TO ROTATE AT
LOW SPEED.
(HIGH SPEED OPERATION)
WHEN THE BLOWER SW IS PUSHED TO HI POSITION, THE CURRENT TO TERMINAL HR OF THE A/C AUTOMATIC AMPLIFIER FLOWS
TO TERMINAL GND OF THE A/C AUTOMATIC AMPLIFIER → GROUND AND TURNS THE HEATER RELAY ON. AT THE SAME TIME, THE
CURRENT TO TERMINAL 4 OF THE BLOWER HI RELAY ALSO FLOWS TO TERMINAL 3 OF THE RELAY TERMINAL FR OF THE A/C
AUTOMATIC AMPLIFIER → TERMINAL GND → GROUND AND TURNS THE BLOWER HI RELAY ON. AS A RESULT, THE CURRENT TO
TERMINAL 5 OF THE HEATER RELAY FLOWS TO TERMINAL 4 → TERMINAL 1 OF THE BLOWER MOTOR → TERMINAL 2 → TERMINAL
1 OF THE BLOWER HI RELAY → TERMINAL 2 → GROUND WITHOUT PASSING THROUGH THE BLOWER RESISTOR, CAUSING THE
BLOWER MOTOR TO ROTATE AT HIGH SPEED.
(MEDIUM SPEED OPERATION)
WHEN THE BLOWER SW IS PUSHED TO M1 OR M2 POSITION, THE CURRENT TO TERMINAL HR OF THE A/C AUTOMATIC AMPLIFIERFLOWS TO TERMINAL GND → GROUND AND TURNS THE HEATER RELAY ON. THEN, THE CURRENT TO TERMINAL IG OF THE A/CAUTOMATIC AMPLIFIER FLOWS TO TERMINAL BLW → TERMINAL 3 OF THE A/C POWER TRANSISTOR → TERMINAL 2 → GROUND.AS A RESULT, THE CURRENT TO TERMINAL 5 OF THE HEATER RELAY FLOWS TO TERMINAL 4 → TERMINAL 1 OF THE BLOWERMOTOR → TERMINAL 2 → TERMINAL 1 OF THE A/C POWER TRANSISTOR → TERMINAL 2 → GROUND AND THE BLOWER MOTOR ISROTATED AT MEDIUM SPEED BY THE A/C AUTOMATIC AMPLIFIER CONTROLING THE CURRENT FLOWING FROM TERMINAL 3 OFTHE A/C POWER TRANSISTOR TO TERMINAL 2.(DEF SYNCHRONIZED CONTROL FUNCTION)WHEN THE DEF SW IN THE MODE SELECTION SW IS PUSHED, A SIGNAL IS INPUT INTO TERMINAL DEF OF THE A/C AUTOMATICAMPLIFIER. THIS CAUSES THE A/C ON AND THE BLOWER SW IS TURNED TO AUTO MODE.(AUTO FUCTION)WHEN THE AUTO SW IN THE HEATER CONTROL SW IS PUSHED, A SIGNAL IS INPUT INTO TERMINAL BAUTO OF THE A/CAUTOMATIC AMPLIFIER. AT THE SAME TIME, THE ROOM TEMP. DECIDED BY THE HEATER CONTROL SW IS INPUT INTO TERMINALTSET OF THE A/C AUTOMATIC AMPLIFIER AS A SIGNAL, A SIGNAL OF THE A/C SOLAR SENSOR IS INPUT INTO TERMINAL TS OF THEA/C AUTOMATIC AMPLIFIER AND A SIGNAL OF THE A/C ROOM TEMP. SENSOR IS INPUT INTO TERMINAL TR OF THE A/C AUTOMATICAMPLIFIER. AS A RESULT, A/C SYSTEM IS ACTIVATED BY THE SIGNAL OF EACH SENSOR TO GET THE ROOM TEMP. DECIDED BYTHE HEATER CONTROL SW AND THE A/C SYSTEM TAKES THE PROPER MEASURES FOR IT.

 

[MikeB]

Have you confirmed whether the problem in the power supplied to the fan, or the mechanical fan itself? You can take the cover off the fan so the power plug is easy to get to. Then drive around normally until you are in the condition where it isn't blowing when it should be. Leave the truck running, pull the power connector off the fan, and see if it is supplying 12v.

 

[djzimms]

The blower resister only comes into play at lower speeds, so if high speed doesn't work, it's not the problem. What works, what doesn't, does the switch panel light up, the A/C button light when pressed, no blower speeds work? FSM available here:

For Sale - 40, 50, 60, and 80 series FSM for a hell of a price.

Both sides of the blower, power and ground are switched, so the problem could be in either side. Set the blower to max, key turned to run, unplug the blower, test the connections, does it have power and ground, if not which one is missing? This cuts the search in half, the problem is on that side of the circuit. Most times, not always, if none of the blower speeds work and everything else works, the problem is on the power side.

1. HEATER BLOWER MOTOR OPERATION
CURRENT IS APPLIED AT ALL TIMES THROUGH THE FL HEATER FUSE TO TERMINAL 5 OF THE HEATER RELAY. WHEN THE IGNITION
SW IS TURNED ON, CURRENT FLOWS THROUGH THE GAUGE FUSE TO TERMINAL 3 OF THE HEATER RELAY → TERMINAL 1 →
TERMINAL HR OF THE A/C AUTOMATIC AMPLIFIER. AT THE SAME TIME, CURRENT ALSO FLOWS FROM THE GAUGE FUSE TO
TERMINAL IG OF THE A/C AUTOMATIC AMPLIFIER AND TERMINAL 4 OF THE BLOWER HI RELAY → TERMINAL 3 → TERMINAL FR OF
THE A/C AUTOMATIC AMPLIFIER AND TERMINAL (B) 13 OF THE BLOWER SW.
(LOW SPEED OPERATION)
WHEN THE BLOWER SW IS PUSHED TO LO POSITION, THE CURRENT TO TERMINAL HR OF THE A/C AUTOMATIC AMPLIFIER FLOWS
TO TERMINAL GND OF THE A/C AUTOMATIC AMPLIFIER → GROUND AND TURNS THE HEATER RELAY ON. AS A RESULT, THE
CURRENT TO TERMINAL 5 OF THE HEATER RELAY FLOWS TO TERMINAL 4 → TERMINAL 1 OF THE BLOWER MOTOR → TERMINAL 2
→ TERMINAL 1 OF THE A/C POWER TRANSISTOR → TERMINAL 2 → GROUND AND CAUSES THE BLOWER MOTORS TO ROTATE AT
LOW SPEED.
(HIGH SPEED OPERATION)
WHEN THE BLOWER SW IS PUSHED TO HI POSITION, THE CURRENT TO TERMINAL HR OF THE A/C AUTOMATIC AMPLIFIER FLOWS
TO TERMINAL GND OF THE A/C AUTOMATIC AMPLIFIER → GROUND AND TURNS THE HEATER RELAY ON. AT THE SAME TIME, THE
CURRENT TO TERMINAL 4 OF THE BLOWER HI RELAY ALSO FLOWS TO TERMINAL 3 OF THE RELAY TERMINAL FR OF THE A/C
AUTOMATIC AMPLIFIER → TERMINAL GND → GROUND AND TURNS THE BLOWER HI RELAY ON. AS A RESULT, THE CURRENT TO
TERMINAL 5 OF THE HEATER RELAY FLOWS TO TERMINAL 4 → TERMINAL 1 OF THE BLOWER MOTOR → TERMINAL 2 → TERMINAL
1 OF THE BLOWER HI RELAY → TERMINAL 2 → GROUND WITHOUT PASSING THROUGH THE BLOWER RESISTOR, CAUSING THE
BLOWER MOTOR TO ROTATE AT HIGH SPEED.
(MEDIUM SPEED OPERATION)
WHEN THE BLOWER SW IS PUSHED TO M1 OR M2 POSITION, THE CURRENT TO TERMINAL HR OF THE A/C AUTOMATIC AMPLIFIERFLOWS TO TERMINAL GND → GROUND AND TURNS THE HEATER RELAY ON. THEN, THE CURRENT TO TERMINAL IG OF THE A/CAUTOMATIC AMPLIFIER FLOWS TO TERMINAL BLW → TERMINAL 3 OF THE A/C POWER TRANSISTOR → TERMINAL 2 → GROUND.AS A RESULT, THE CURRENT TO TERMINAL 5 OF THE HEATER RELAY FLOWS TO TERMINAL 4 → TERMINAL 1 OF THE BLOWERMOTOR → TERMINAL 2 → TERMINAL 1 OF THE A/C POWER TRANSISTOR → TERMINAL 2 → GROUND AND THE BLOWER MOTOR ISROTATED AT MEDIUM SPEED BY THE A/C AUTOMATIC AMPLIFIER CONTROLING THE CURRENT FLOWING FROM TERMINAL 3 OFTHE A/C POWER TRANSISTOR TO TERMINAL 2.(DEF SYNCHRONIZED CONTROL FUNCTION)WHEN THE DEF SW IN THE MODE SELECTION SW IS PUSHED, A SIGNAL IS INPUT INTO TERMINAL DEF OF THE A/C AUTOMATICAMPLIFIER. THIS CAUSES THE A/C ON AND THE BLOWER SW IS TURNED TO AUTO MODE.(AUTO FUCTION)WHEN THE AUTO SW IN THE HEATER CONTROL SW IS PUSHED, A SIGNAL IS INPUT INTO TERMINAL BAUTO OF THE A/CAUTOMATIC AMPLIFIER. AT THE SAME TIME, THE ROOM TEMP. DECIDED BY THE HEATER CONTROL SW IS INPUT INTO TERMINALTSET OF THE A/C AUTOMATIC AMPLIFIER AS A SIGNAL, A SIGNAL OF THE A/C SOLAR SENSOR IS INPUT INTO TERMINAL TS OF THEA/C AUTOMATIC AMPLIFIER AND A SIGNAL OF THE A/C ROOM TEMP. SENSOR IS INPUT INTO TERMINAL TR OF THE A/C AUTOMATICAMPLIFIER. AS A RESULT, A/C SYSTEM IS ACTIVATED BY THE SIGNAL OF EACH SENSOR TO GET THE ROOM TEMP. DECIDED BYTHE HEATER CONTROL SW AND THE A/C SYSTEM TAKES THE PROPER MEASURES FOR IT.

I'll have to check on which lights are on/off, but none of the blower settings work at all when the issue arises. I believe that all the lights actually do come on, but nothing happens. This issue occurred around the same time I disconnected the clock to install a monitor for a wireless camera. Had some trouble getting the wires back together and the wiring is different from what others have stated is in their rigs. Here's that discussion: Clock Wiring Help - Putting Back Together Essentially, I connected the 2 ground wires coming from the clock to the one ground wire being sent from the dash, and matched up the other wires by color, again matching two to one wire in multiple cases. I was able to get the clock on, but now the weird issue I have is that when the overhead lights are turned to be on when the doors are open, they actually turn on when the doors are closed and are very dim vs. full power. Oh yes, and the clock resets to 1:00 after turning the car off on. So, I have issues there, which could also be impacting the AC as well I suspect.

 

[djzimms]

The blower resister only comes into play at lower speeds, so if high speed doesn't

Thanks for all the info. I cleaned up the Air Amplifier Assembly (near the throttle) and took it for a spin. It first turned on as it typically does when sitting in shade, but, after driving a couple of miles while sitting at a light, I turned off the car and back on and it right away went out. You mentioned important to know what's going on with the lights and all 3 center lights, AC/Auto/Internal-External were out while all top and bottom buttons stayed on with no blower action. Along the short drive, the system turned back on all of a sudden, but then I stopped at another light, turned off the vehicle, and it went off again and would come back on.

I then pulled the other amplifier assembly behind the glove box and cleaned it out. It didn't show any corrosion like the one near the throttle but there was a ton of dirt, some caked on. I cleaned the circuit board, and cleaned up some of the other wires in the area. I also turned the AC unit to manual vs automatic (and that caused the exterior air button to light up on the middle three vs. all center row being off). After some time to dry, I took it for another spin b/c I need to go through a drive cycle to get the engine light off for emissions. After about 45 minutes, I was stopped at a light and turned off the car and back on and then all of a sudden, the AC came back on, and to me, seemingly blowing harder that it did before, and the vent for a lack of better description that's by your crotch, was blowing cold air, which I don't recall that vent blowing anything in years. I could also hear something clicking on/off behind the glove box, and when it came on, the vents blowed harder and dust was coming out like crazy each time I heard it click on...but, it wasn't consistent. I turned the ignition on/off quite a few times and it was staying on. I switched back to automatic vs. manual on the AC unit, and again turned the ignition on/off again, and after a couple of times, the whole unit went off and hasn't come back on again. Once I got home, I cleaned the amplifier assembly again behind the glove box and sprayed off the dirt in the area on the other connections. I left it all open to dry out over some time.

So, after cleaning the 2 amplifier assemblies and some of the other areas around behind the glove box, the system seemed to function fully (which, I wasn't even aware it wasn't blowing full previously), and the blower came on still intermittently, but seemed to be at least a little more than usual when it's hot. Not sure if the manual/automatic setting really made a difference on anything but figured I'd throw it out there.

The 2 small (inch diameter or little more) cylinders what I assume are relays above the heater unit (I think that's what the bigger component in plastic is from other posts) behind the glove box, I wasn't sure how to get those out and clean them and I didn't want to force them. Do you pull those straight out, or is there another method to safely remove and clean them off?