Does anyone here have a copy of the electrical diagnosis chapter from the factory service manual for 1987 Camaros? I bought a used copy
of the manual, but discovered it does not include the electrical diagnosis section.

The problem I am trying to chase is that the primary fan does not engage immediately when I turn the AC on. The fan works when triggered by coolant temperature. The AC works, although not great at idle on a hot day because the fan doesn’t engage. 1987 is a unique year for the fan circuit. The secondary fan is only switched on by the coolant temp switch in the passenger side cylinder head. This also works. There is no refrigerant pressure switch in the high-pressure line that you would find in an 88+ car. Only the low pressure clutch cycling switch and the overpressure protection switch. So what I am trying to understand is how the AC is supposed to trigger the primary fan. What input is the ECM taking to decide to turn the fan on when the AC is switched on? Any advice or documentation here would be great appreciated.

 

See attached. Sorry the schematic isn't in color.

 

Thank you so much! That AC control head test procedure is exactly what I was looking for. It looks like I’m in the market for a new HVAC control unit.

 

I had this problem/// mine turned out to be a short / corroded wire at the relay.