Hi- the ac in this Jimmy has always worked great. The electricals? A little more iffy which is why I think this MAY be more electrical. Im no professional by a mile which is why I’m here.
the controls to the ac dont do anything. It blows cold air thank goodness but after I cut the suv off it still runs. It’s not the engine fan-it’s the interior blower. Which kills the battery quick. So every time I go somewhere I have to disconnect the battery and pray it starts.
Any thoughts and ideas are appreciated. Of course this happened on a hot Saturday night.

 

Do you have and know how to use a digital multimeter?


George

 

I have a digital multimeter and am familiar with it. Im not even sure what to check in this case. Today, the air and everything worked ok until I let it idle a little. I try not to do that but with the heat and situation I have to.
afterward, just for a bit, the controls were all responsive, except #4 setting on the fan. That makes me think to target the fan?

 

Manual or automatic AC?

George

 

I am sorry (I’m laughing) but I’ve never realized there was a difference. Im assuming automatic? Manual sounds like a fan blowing over a block of ice!
There are 3 *****, fan, temp and setting, and a separate rear defroster. Im glad it’s “working” and set to ac with the heat, but it’s acting so wonky.
I should mention I have a lot of electronics rigged up, but I watch the electrical draw.

 

The circuits are completely different so I cant help you until we figure out which one you have.

Manual:




Automatic:




George

 

That’s interesting. I had no idea there were 2 different units. Mine is manual though for sure.

 

You said that the blower motor stays running when you pull the key out of the ignition. Is this true on all four Fan speeds? Does the blower speed change with the selector switch with no key in the ignition? Did you also say that the top fan speed does not work even when the truck is running?

George

 

You are so generous to help me with this.
At first the fan remained on with no key in the ignition, and the ***** did nothing. For about 2 days while I was figuring out what to do. I was unhooking the battery cable to cut it off every time I parked.
suddenly, it became responsive again but now when I turn the fan **** it does nothing on #4. But at least I can cut it off and it’s blowing cold on 1-3.
Im grateful for that with the heat we’ve been having.

 

There are two choices. One would be the parts canon where you could replace either the dash control module and/or the relay to see if you get an improvement in behavior. I did not include the resistor Network on this list because if you only have failure on fan setting four, that setting does not use the resistor Network and so that would not be the problem.The second option is to open the dash up and get access to the back of the controller and using a meter start running some experiments to find the problem through diagnosis and do a targeted repair.

George