First is my right turn trailer circuit is getting low voltage back to the lights. My trailer had a bad spot in the harness. Some wires got melted together. I think it damaged something in the trucks circuit. I get turn signals on the tractor correctly. On the trailer I get left turn , but right turn is very dim, only showing about 5 volts making it to the back. Is there some sort of replaceable flasher relay I can change. The truck has a signal Stat 900 turn signal switch. Second issue is a/c compressor won't disengage, unless I unplug it. Have also tried unplugging the high pressure switch. Also tried removing the high pressure switch and pluging it back in. I also believe this problem is causing my engine fan to stay on, as it won't disengage either.
Is your heater set on defrost? The A/C is automatically on with defrost on some heating systems and that can include the fan being activated. The theory is to dehumidify the air blowing onto the windshield.
Unfortunately it doesn't matter what position the switch is in. Although that is a point I had not considered. The vents do change with the switch. I was hoping someone else had solved this problem. I may have to start disconnecting all the wiring in the AC system one by one
With the ignition switch turned off, you should be able to view the ac compressor clutch, it should be disengaged.
Let's start with what model truck and year? Crap, that was the first thing you wrote, sorry. I would recommend you get this - Amazon.com What is the voltage at the plug? 5 volts?
Does it have a fan switch also? Located on dryer next to high/low pressure switch. Need to identify switches, find out exactly what they are. There’s bianary and sometimes trianary switches that have 3 functions all in one switch.
I do have one of those. Although I have been a little disappointed with it. Those male prongs loosened up on mine resulting in me losing one of the prongs
I do have a dash switch for the engine fan. The pressure switch is a 4 prong. It was recently replaced. No change. Unplugging it
Unplugging it made no change. I plugged the old switch back into, but not screwed onto the drier. No change
