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FFNPMcD · Joined: 15 Aug 2013 Posts: 19 Location: Richmond, Va.

If you followed my last couple of posted questions you will see I recently replaced my thermostat and coolant temperature switch...
I believed everything to be in order but noticed today that the switch to control cabin air (blower?) on the interior temperature controls is no longer functioning...

What have I done?
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1987 924s

FFNPMcD · Joined: 15 Aug 2013 Posts: 19 Location: Richmond, Va.

Update:

After the vehicle had been sitting a while I got in to move it and the blower was working. When I turned on the AC the blower cut off again.
It seams as if enguaging the compressor on the AC causes problems with the blower fan control..
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1987 924s

edredas · Joined: 09 Dec 2004 Posts: 861 Location: Charlotte, NC

The work that you have done previously shouldn't have any effect on the blower motor operation...

You could have a bad wiring/switch, bad relay, or the fuse could be melted causing intermittent contact. Also, the green resistor next to the motor have been known to burn out, but that usually causes problems with one setting.

It has been a long time since I've ran A/C in my car, but there are two motors and I don't remember them working at the same time... I want to say that when the A/C is on the outside blower is turned off and only the A/C blower under the dash runs... if that is correct, then maybe there is a fault there. Maybe someone with A/C will chime in.
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'84 944 -White, Brown interior
'84 944 -Red, Automatic
'86 944 -Garnet, Fully loaded, Koni suspension
'87 924S -Red, 300hp 951 swap
'87 924S -Red, Project Car
'88 924S -Red, Daily Driver