AC Fan switch

[supernovatx]

I have the bastardized AC with the evaporator hole cut in the passengers footwell and since I got the AC running I've noted the on/off fan speed switch gets hot to the touch. I've read the past threads on this about cleaning the connectors and have since replaced the switch and it still got hot. So I've now replaced the wire from the switch to the fan as it attaches directly to the fan motor and it's still getting hot.

So my thoughts are putting in a relay after the switch so it draws it's power directly from the battery instead of the switch. Does this make sense or am I missing something?

[86 911 Targa]

Originally Posted by supernovatx

I have the bastardized AC with the evaporator hole cut in the passengers foot well and since I got the AC running I've noted the on/off fan speed switch gets hot to the touch. I've read the past threads on this about cleaning the connectors and have since replaced the switch and it still got hot. So I've now replaced the wire from the switch to the fan as it attaches directly to the fan motor and it's still getting hot.

So my thoughts are putting in a relay after the switch so it draws it's power directly from the battery instead of the switch. Does this make sense or am I missing something?

Please tell us more about your car's model/year and "bastardized A/C"

The fan speed is controlled by resistors which are located in the passenger foot well which might be defective.

Also, you may have a grounding issue.

[supernovatx]

It's a 76 911s and I've the aftermarket evaporator/fan that had a ~6"x8" hole cut in the body wall to the smugglers box. It was well done but it is not the factory model. I don't know whom the manufacture was but originally the car was out of california.

The AC works fine its just the high speed setting wire connector to the fan switch gets to hot. Thanks, John

[86 911 Targa]

Originally Posted by supernovatx

It's a 76 911s and I've the aftermarket evaporator/fan that had a ~6"x8" hole cut in the body wall to the smugglers box. It was well done but it is not the factory model. I don't know whom the manufacture was but originally the car was out of california.

The AC works fine its just the high speed wire to the fan gets to hot. Thanks, John

I "assume" that the aftermarket installation included some type of resistor circuit to control the fan speed(s).

As you can see by the schematic, the high speed setting (#3) bypasses these resistors
suggesting that your fan should be directly wired to the the switch.

Can you trace out the wire from the high speed contact on the switch (#3) to It's end connection on the motor?

Look for a shorted wire.

Gerry

[wwest]

Originally Posted by supernovatx

I have the bastardized AC with the evaporator hole cut in the passengers footwell and since I got the AC running I've noted the on/off fan speed switch gets hot to the touch. I've read the past threads on this about cleaning the connectors and have since replaced the switch and it still got hot. So I've now replaced the wire from the switch to the fan as it attaches directly to the fan motor and it's still getting hot.

So my thoughts are putting in a relay after the switch so it draws it's power directly from the battery instead of the switch. Does this make sense or am I missing something?

Your problem is either high resistance switch contacts or poor connectors to/at the switch. Solder the wires directly onto the switch lugs and see if that helps.

[supernovatx]

So I pulled the box out containing the blower/evap and one of the wires inside had been poorly spliced. So I spliced it properly and tested the system again and now all is well. I'm not sure why this caused heating at the switch but it fixed the overheating problem.

Thanks guys

[86 911 Targa]

Originally Posted by supernovatx

So I pulled the box out containing the blower/evap and one of the wires inside had been poorly spliced. So I spliced it properly and tested the system again and now all is well. I'm not sure why this caused heating at the switch but it fixed the overheating problem.

Thanks guys

Series resistance.