Need some advice about a 1990 4runner V6 3.0 I recently purchased. My A/C condenser fan (just behind grill) is acting erratically:

1. Comes on when A/C not deployed.
2. Continues running often after engine shut off, even when everything cool (and A/C has not been used). When engine warm, it can cycle on and off for a long time. (So far, hasn't drained battery.)
3. Opening or shutting back gate or doors can trigger fan to start or stop.

From reading other posts, it seems likely that my fan sensor relays 1 or 2 (or both) are either faulty or have dirty contacts. I notice that the box they are in (SB3) is missing its top.

Does the behavior noted suggest a particular relay of the two or more likely other wiring problems? (Any ideas on finding a top to the relay box appreciated as well!)

 

Demons You need to wash your Truck With Holy Water!!

Since this motor is a switched ground something in that circuit is allowing it to ground.

As it seems to be random I would think a wire touching someplace

Could be either of the relays or in the harness someplace .

 

Relay #2 has to be closed for the fan to come on. Relay #1 just switches between hi and low fan speeds. Normally Relay 2 is switched by the same signal that switches the magnetic clutch on the compressor. Is the compressor coming on randomly as well, or is it behaving normally?