I've been working on my A/C issue. It wouldn't come on. So I tested the following, Power at the fuse and relay good. Power to the clutch no good. Jumpered the relay and the clutch works. Start truck then jumper relay and A/C works great. So my question is, could this be a case of a bad control panel or is there something in between I can check?

Thanks!

Edit: I know I have a blend door actuator issue, Meanwhile I have removed it and manually set to door to the correct position. Second question, does the blend door position get reported to the PCM and prevent AC if it is not moved to the correct spot?

 

Are you saying your ac switch only works with the truck running?

 

No, The AC and Max AC functions do not engage the clutch. If I put it to Max AC and manually jumper the clutch relay, the AC then works.

edit: forgot to mention that the relay is good. I've changed it with other relays and they continue to work.

 

Update: I let the AC run yesterday for about 20 min while the truck idled, no problems. Moved truck into the shade while AC was jumpered on. AC cut out and instant hot. Turned truck off, then back on after 30 min. jumpered AC and it worked again. So not the control panel I am assuming. If anyone has any idea I'd be very grateful. Its hot.

Thanks everyone!

 

It might help if you EXPLICITLY identified what you are working on, identified exactly what pins you're jumping, which control panel you, etc. Eliminates the 20 questions game.

 

Not sure why identifying the exact pins I used to jumper make any difference. If I jumpered the correct pins and the clutch engaged then the proper pins, 30 and 87 were used. The control panel is exactly that. Where you control the functions of the HVAC system. I'm an electrical engineer, a building engineer and a US Navy mechanic. Everything I've stated is exactly how it is. I am just looking for some help with this to make it easier. Military equipment is much easier to work on and trace the ghosts out.

Thanks!

No offense meant.

 

If the relay is good and jumping the relay temporarily fixes the problem then I'm thinking either
1. There's an intermittent short somewhere
Or
2. Maybe the sockets for the relay have corrison built up on them? Causing for the lack of a good enough connection until you put the jumpers in there and make better contact?

When it's not working have you verified you have power to the input side of the relay? If yes then it has to be either the relay or the sockets for the relay.

 

There is zero corrosion. Kind of surprising. I also did the "wiggle test", power on, meter on each contact, wiggle incoming harness to the fuse panel. No irregularities detected. I have verified power on the input side to be good at all times.
Is there possibly a common short point among these models? Or more likely just a random thing. Also for my second post on this, does the blend door position get reported to the PCM and prevent AC if it is not moved to the correct spot? I could see this also being the case since my current part is dead and stuck in the heater position. Maybe that's just overthinking it but it is a genuine possibility in theory.

 

Which SPECIFIC vehicle are you working on? Without that critical bit of information diagrams, procedures and protocols cannot be accessed.
Which SPECIFIC climate control system is installed? There are two control systems, manual or electronic automatic. If you do not identify which you are working with diagrams, procedures and protocols cannot be accessed.
There are MULTIPLE (3) pins on most of these systems that could have been jumpered at the relay to force the clutch to energize. Without knowing which pins were jumpered, it is not possible to follow a logical analysis of your actions.
Do you exercise this lack of precision on your day job?
No. The PCM has no input from the blend door actuator system.

No offense meant.

 

My profile has all of the specifics of the vehicle.
My job(s) have people that understand the obvious and the ability to look into details without handholding and constant questions. We work well on our own and everything is detailed in notes and documentation, as I have done in my profile.
In the field, with no ability to instantly contact someone, we are on our own to look into the sets of documentation. Don't question my job performance or ability. I've done more than most people ever have. This is a basic question that is not well documented. I am asking some people that may have some quick answers. I don't need someone to question my job/work ability.