Jim bailey - 928 International

the 1978-86 the electric fan should NOT run when the ignition switch is off... note there are no warnings about the "fan may start at any time" on the early cars. The very brown 1980 at the track I often switch the ignition on so the fan will run between sessions and cool down the radiator.

neilh

Jim, the 81 owners manual says otherwise:

Jim bailey - 928 International

OK looks like it may have been changed ...the 1980 does not run wifes 79 did not run but the 81-86 does have constant power so a defective temp switch could run forever...

kipdo

Thanks for the response. I will check the relay this weekend. The heat here in Tucson is brutal. Kip

puyi

Hi,

I have the same problem on my 90 GT. I Thought, relays or fuses or switches were responsible for that. But the problem is not constant. So I did nothing other than just keep cooling fan for several minutes and then restart engine, in order to reactivate cooling pump for few seconds and shut down engine. Then, few minutes later the cooling fan usually shut off.

I will change temp switches and hope it will be OK.

STL

Mrmerlin

Hi make sure to check the fan switch in the radiator, this switch sticking on will make the fans run till the battery is dead, if you rad fan switch is older that 10 years it might be a good idea to replace it, look at the driver side lower front of the radiator for the switch connection

H2

Since my problem started just after I got the car back from a mechnanic...is there a chance that two wires on a switch might have been replaced in reverse, causing the problem?

H2

Loaded

intake temp switch was my culprit try it

Gretch

Bigs................"convection".

T_MaX

Those with automatic transmissions will need to test the temp sensor on the trany! It is hooked up in line with the intake air temp sensor! The connection for this sensor is under the rear floor (trunk) mat.

T_MaX

No chance!

k1woods

Temp sensor on the tranny? that's crazy talk

84 S2

dr bob

May be crazy for pre-S4 cars, but for the rest of us it's a real deal. Since our subject car is pre-S4, we can cut that switch out of the 'possible causes' list.

Eliminate the temp switch on teh radiator from that list by pulling the wires from it. As others mention, front side bottom of the radiator, left side of car (right side looking from the front), under the AC condenser. With wires disconnected, if fan stops, switch is your problem. There's also a fan relay that might be sticking, and AC switch. What did your mechanic work on just before this problem started?

Normy

-The problem I had with my car was that the air conditioning was weak. Thinking that I needed a re-charge, I took it to a reputable local AC shop, and they determined that not only was it low, but the aux fan wasn't coming on either.

Quick fix: I jumpered the two wires at the temperature sensor in the radiator; now whenever I turn on the ignition, the fan runs. It shuts off when I turn on the ignition off, but never comes on afterward as it should on hot days. The fan comes on after you shut the engine down in order to reduce under-hood temperatures [which can lead to fuel vaporization in the rails], and I suspect that the air temperature sensor underneath the intake tube for cylinder #2 controls this. In my case, it is either a bad sensor or it has a bad wiring. One more thing to work on...

In any case, I've run around for a couple years now with the fan jumpered, and even on hot summer days in Florida, stuck in traffic, my temp gauge barely goes above the first tick.

Just one idea...

N!

kipdo

I just had a water pump and idler bushing replaced. The PO had the whole WP/TB service done a year ago March & 5K miles. Have burped the system. Just running at the top white line when temps are 100 +.Thanks Kip