Help! HVAC - no fan, auto stopped working
- Thread starter LLTB
- Start date
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- Thread starter
- #22
Resurrecting this old thread.
I threw money at this problem a year back. Replaced the climate controls module (the thing with the A/C and Heat buttons/controls on it) with a good one from someone here on the forum. I also replaced the MAIN HEATER FAN RELAY located in the driver side kick panel on the relay block, Part 90987-04002, and also replaced the A/C Amplifier located behind the glove box from one off of eBay. After that, my system worked just fine for the past year. No intermittent issues. For good measure, I paid the dealer to replace the gasket seal around the windshield properly with a new one. I did have a windshield leak, so I wanted to prevent any future problems. I have not had water in the cab since.
This week the HVAC intermittent problems returned. Coincidentally, this happened right after I was driving through the most incredible rain downpour I've ever seen near Moab, Utah. It was unreal. I did not see any water in the cab, but the HVAC went on the fritz and quit working reliably. I can't say that this is what caused it to stop working again, and with a new dealer-installed windshield gasket, I'm not convinced it was the rain, but it sure is a strange coincidence that it stopped working about 10 minutes after we drove through that rainstorm.
Back to troubleshoting.
Today I removed the climate control module (with the buttons and controls) and also the A/C Amplifier behind the glove box. I disassembled them to check out the PC Boards and make sure there were no broken solder connections or heavy oxidation. I used some QD Contact Cleaner and sprayed the PC boards on both sides and used a gentle brush to clean them and patted them dry. Finally, reinstalled everything and replaced the main heater fan relay 90987-04002 in the kick panel relay block for s***s and giggles.
Is there another module/component to this system somewhere? Previously in this thread someone mentioned a WHITE "A/C Amplifier" located near the driver's knee. I haven't ever been able to locate this.
I just want to make sure I've reviewed all the components. It's friggin cold so I've been avoiding driving the cruiser.
I threw money at this problem a year back. Replaced the climate controls module (the thing with the A/C and Heat buttons/controls on it) with a good one from someone here on the forum. I also replaced the MAIN HEATER FAN RELAY located in the driver side kick panel on the relay block, Part 90987-04002, and also replaced the A/C Amplifier located behind the glove box from one off of eBay. After that, my system worked just fine for the past year. No intermittent issues. For good measure, I paid the dealer to replace the gasket seal around the windshield properly with a new one. I did have a windshield leak, so I wanted to prevent any future problems. I have not had water in the cab since.
This week the HVAC intermittent problems returned. Coincidentally, this happened right after I was driving through the most incredible rain downpour I've ever seen near Moab, Utah. It was unreal. I did not see any water in the cab, but the HVAC went on the fritz and quit working reliably. I can't say that this is what caused it to stop working again, and with a new dealer-installed windshield gasket, I'm not convinced it was the rain, but it sure is a strange coincidence that it stopped working about 10 minutes after we drove through that rainstorm.
Back to troubleshoting.
Today I removed the climate control module (with the buttons and controls) and also the A/C Amplifier behind the glove box. I disassembled them to check out the PC Boards and make sure there were no broken solder connections or heavy oxidation. I used some QD Contact Cleaner and sprayed the PC boards on both sides and used a gentle brush to clean them and patted them dry. Finally, reinstalled everything and replaced the main heater fan relay 90987-04002 in the kick panel relay block for s***s and giggles.
Is there another module/component to this system somewhere? Previously in this thread someone mentioned a WHITE "A/C Amplifier" located near the driver's knee. I haven't ever been able to locate this.
I just want to make sure I've reviewed all the components. It's friggin cold so I've been avoiding driving the cruiser.
You have the best resource in the factory service manual; unfortunately, the A/C section is very long so grab some beverages and start reading. The troubleshooting section starts on page AC-3 and runs through AC-4, but I'd start on page AC-93.
Just a minute
1997 service manual
1997 EWD
Both are in the Resources Forum, 80 series section, along with loads of other good to know stuff. I just verified both links.
1997 EWD
Both are in the Resources Forum, 80 series section, along with loads of other good to know stuff. I just verified both links.
- Thread starter
- #27
You're a life saver. I was looking in the wrong place. I was in the 80 Series Tech Forum looking at the pinned "Resources" post.
Thank you so much. I'll start reading.
- Thread starter
- #28
So according to the FSM, possible culprits for no blower operation could be:
It doesn't mention anything about intermittent blower fan operation, but I suppose that this list would be the same regardless.
- HTR Fuse
- Heater Main Relay (page AC-88) -- I've replaced this
- Blower motor (page AC-72)
- Blower resistor (page AC-78)
- Blower speed control switch (page AC-93)
- Wire harness
It doesn't mention anything about intermittent blower fan operation, but I suppose that this list would be the same regardless.