My question is about how this switch works, and how it is connected ?
is it a sort of transistorized relay ?
how is it connected ?
is it a sort of transistorized relay ?
how is it connected ?
Air Conditioning aux FAN connections
- Thread starter deQuincey
- Start date
edmil
New Member
Hi
I have been having a related discussion with HBChris under the thread Auto Choke Relay. My 73 Auto Coupe developed a problem in that the auxiliary fan came on as soon as the ignition key was turned.
I mistakenly assumed that the wiring diagram in the blue book for the auxiliary fan in some way related to my car but it is dated 1.76.
The wiring for the auxiliary fan in the earlier cars is completely different. I have attached a diagram I have made of the system in my car which shows the thermo switch. This is shown in the parts book as related to the air conditioning (which my car does not have).
My question too is what does this do.
I have not yet traced the path of the brown/white wire from the thermo switch but suspect it connects to the temperature gauge on the dash.
The problem I had seems to have cured itself, but don't hold your breath.
Attachments
DeQuincey- I shipped a relay to you on Friday, it is at San Francisco airport waiting to be put on a plane. I sent you tracking info.
the schematic is on the label.
the schematic is on the label.
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The thermo switch shares the male spade connector on your temp gauge sender at the thermostat housing. 2 brown/white wires there.
if your thermo switch is activating- disco the spade at sender to test for bad sender, check for short on brown/white wire, disco black/white wire at relay to test for faulty thermo switch
if your thermo switch is activating- disco the spade at sender to test for bad sender, check for short on brown/white wire, disco black/white wire at relay to test for faulty thermo switch
The thermo switch is found on 74 coupes with A/C and activates the aux fan when A/C is off if the temp sender reaches its limit. It only shares a switched power source (green/white) from the ignition, they are not otherwise related to each other. BMW even uses this same green/white wire to the choke relay to power the chokes and to trigger the chokes when a ground is completed doing double duty.
I have never seen an aux fan in a coupe without A/C, doesn’t mean it can’t be in a few cars I guess but I would think a PO added it. And the connector for the aux fan in the diagrams just shows a power source, how it would be used is anyone’s guess. And the A/C aux fan gets power directly from the battery to a relay under the coil with its own single fuse holder, not from the fuse block. Could it be a source for the A/C relay trigger? Maybe, but on an A/C car that comes from the A/C temp switch in the console. All pretty strange and confusing. Can you post a pic of your aux fan, I know it might be very hard to see.
I have never seen an aux fan in a coupe without A/C, doesn’t mean it can’t be in a few cars I guess but I would think a PO added it. And the connector for the aux fan in the diagrams just shows a power source, how it would be used is anyone’s guess. And the A/C aux fan gets power directly from the battery to a relay under the coil with its own single fuse holder, not from the fuse block. Could it be a source for the A/C relay trigger? Maybe, but on an A/C car that comes from the A/C temp switch in the console. All pretty strange and confusing. Can you post a pic of your aux fan, I know it might be very hard to see.
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thank you so much
i asked for your paypal address to pay my debts, see my pm please
regards