So the compressor isn’t turning on at all. Only had the truck about a year now, and didn’t drive it much last summer. This is the first time using the ac now that it’s 90+ outside. Went to the ac relay RL3 and put a jumper in place of it, and the compressor turns on, ac blows nice and cold. Had an extra relay, swapped that, still no go. Checked for power on the control side of the relay, no power when commanded on. What should I be checking for on the control side? Also I should mention that the hvac display didn’t work when I got it, so I got a replacement off eBay. Reading up here, I see that pre and post 99 models have different way of controlling the ac compressor circuit. No idea what year my hvac controller came out of. Going to check that next. Vehicle is a 2001 though. Also when I had a jumper in place of the relay, I noticed the electric fans did not turn on. Just started the engine and it was cold, but should the fans come on if the ac is activated?

 

I’m not really familiar with the AC system, but I would definitely be suspect of the HVAC coming from a GEMS instead of Bosch.
Also (dumb question but you never know) my GEMS P38 HVAC control has a button to turn off AC.

 

Also, I’d need to read up on the fans. You’re right that the AC controls them.

 

Figured it out this weekend. So I did have the older version hvac controller. Bypassed the relay with a jumper so it powers the ac clutch directly, and it works. Funny thing is that I tried this earlier during diagnosis but the vehicle was running. The relay was installed, and I swapped in a jumper and it didn’t work. The controller sensed no load and stops the output to the ac clutch until the next key cycle. So key off, jumper installed, start it up again, and I have ice cold ac. Perfect timing too. It’s hot this week and very humid already today. But as per usual, fix one thing and you find more items to fix. Evaporator is leaking water on the drivers side floor area now

 

Good to hear that it’s working. As for the water, I you’re probably expecting a plugged or broken drain hose?

 

Just plugged luckily. Had it on the lift at work and blasted the drains with a little compressed air. Nice and clean now. Nice having an ac system with 3 lbs of refrigerant. It was very humid today and it stayed ice cold the entire time

 

Great. My P38 ac works really well. The D2 about 3/4.

 

hi, any possibility you can draw me a diagram or even a picture or video on how to bypass the relay? And which one exactly it is? Not that mechanically incline but trying to save a $ and not melting at the same time lol.




QUOTE=Greendisco12;777381]Figured it out this weekend. So I did have the older version hvac controller. Bypassed the relay with a jumper so it powers the ac clutch directly, and it works. Funny thing is that I tried this earlier during diagnosis but the vehicle was running. The relay was installed, and I swapped in a jumper and it didn’t work. The controller sensed no load and stops the output to the ac clutch until the next key cycle. So key off, jumper installed, start it up again, and I have ice cold ac. Perfect timing too. It’s hot this week and very humid already today. But as per usual, fix one thing and you find more items to fix. Evaporator is leaking water on the drivers side floor area now[/QUOTE]