I had my A/C worked on last week. The compressor wont engage unless jumped. When its jumped and running, it works great, blows cold. My question is why am I having to jump it. The wire going to it is hot. 11.6 volts. The weird thing is that its VERY dim on my test light compared to similar voltage. Anybody have any suggestions.
On newer vehicles there is a pressure switch, that if the pressure is too low, it will not engage the compressor. Not sure if our older cars have something similar, but just throwing out ideas...
I guess it depends on what you mean by jumped... On my older explorer, it has a slow leak, I add a can every year. When I have to add, the compressor will not cut in, even when trying to add the freon. So I have to jump it at the compressor to get it to come on, and then it will suck the new freon. I can then disconnect the jump, and it runs fine... for a year... almost...:TU:
Check the engine ground strap between the firewall at the regulator & the rear of the RH side head. This is an alternate path to the battery cable, which should be secure at the block,on the lower AC bracket. New paint can cause grief here as well. Also, black wire at the upper AC bracket should have good conductance where connected. I've seen new paint on the bracket kill the ground path.
