So I thought I would start a thread for this. There are many threads out there on AC troubleshooting, but no specific advice on replacing The AC amplifier (A/c or HVAC control module)
First this is a fairly easy repair. If you can change the HVAC control backlights, you can do this. It does not require ripping apart the entire dashboard like you may read (or I read) or like with the evap core temperature sensor. Similarly, the part is about $40-50 on ebay and requires only 30-60 min of your time.
What does this part do - basically, my understanding is that it helps match the speed of the AC compressor and clutch to the speed of the engine belt/ RPMs of the engine
Signs of mine failing - blinking AC light and no cold air. I should note that my mag clutch blew out and so there is a chicken or an egg thing here (did my bad amplifier cause the clutch to fail or bad clutch cause this to fail or were they coincidental)
- I ran through the troubleshooting for blinking AC light. It was not the MAG clutch relay. By jumping this relay with a paperclip in the fusebox, I was able to get the compressor to work and turn on. My low pressure was ~40psi at 70 degrees. I checked all the other connections best I could and could not find an obvious problem
- So my AC light would stay on if I pressed it when the key was in the on position, but the engine not started (obviously would not blow cold air since the compressor is not on)
- There is a diagnostic code mode by pressing and holding the auto and recirculate air buttons at the same time while turning the key to the on position. Mine showed 00 - no codes. Similarly with an OBD2 reader at autozone there were no engine codes
Replacement
So I wish I had pictures and next time im in this I will try to add some.
There are two amplifiers - one for Sr5s [PT # 88650-35250], and one for 4r with dual climate control (ie limited) [PT # 88650-35260]
Im not sure where the sport edition falls in
Your best bet is ebay
THis video will help if you havent done this before. You do not need to take out the radio/ headunit.
2003 - 2009 Toyota 4Runner Touch Screen Radio Install | Pioneer AVH-X2700BS - YouTube
1. Below the HVAC control is a pop out tray. Pop this out and pull up and out to remove this.
2. behind this is a 10 mm bolt. Remove this bolt and put in a safe place.
3. Make sure your keys are out or battery disconnected. Pull up and out on the HVAC control module to remove this. Remove the electrical harness. Please note that you should not the turn 4r on while this harness is unplugged. It messes up the air bag module and is reportedly pretty expensive to have the dealership reset this.
4. Open the center console storage. just infront of this is a little storage tray. Pinch the plastic trim/ bezel on either side and pull up to snap out. I recommend removing the harness for the DAC button and lifting this trim over the gear selector and out of the way.
5. remove the the protruding circle around the key hole for ignition that tells you what direction to turn the key
6. For the large plastic panel below the steering wheel, remove the two 10 mmg bolts at the bottom corners.
7. From the trim around the HVAC controls and radio/ headunit, disconnect the wiring harnesses for 4WD, rear window up and down and emergency flashers.
8. You can then pull the trim with air vents and 4wd button etc out to give you some room
9. Behind where the HVAC control was, there is the AC amplifier. Remove the two wiring harnesses on the driver side and the 3 bolts holding it in.
10. Swap with your new (or likely used as the case may be), put everything back together and hopefully that fixes your issue!
Let me know if anyone has any questions. and Ill try to add pictures for the future
Linear Mode
