cooling fan question/ confusion

[RR Guitars]

I have a '87 924s 2.5 non-turbo have 2 fan set up w/ drivers side fan works fine, passenger side fan,works only if i put plug from drivers side fan. question: should both fans work together, or does a/c switch control one, and rad. thermal switch control the other. I know that John AZ has stated in several post that our cars should run with temp. gauge at around half and set fans off at about 3/4, at that point i still get only one fan, maybe different relays for different fans HELP ! Also have to do some work on window wipers VERY grindeee need grease really bad, any before hand info would be helpful.

[Guest765]

The AC switch turns on one fan only and in low speed. If the fan works when you swap the plugs then its time to trace out and check the ground point and also check the offending plug and wires for damage. There is also a resistor pack you can check which on the later cars is under the dash behind the glovebox.

[Timmay!]

If the car is maintaining temp, it's working ok.
As mentioned , Cooling fan comes on at 3/4 and cools until it hits 1/2 on the gauge. Turn on your A/C and see if your right fan comes on.
There's 2 different fan systems. 83-85.1 and the other 85.2 and up. Early has 3 bladed fan- late has 6. Early has small relay, late has "double can" silver relay. There's a nice write up on the differences and trouble shooting on clark's garage website.