can't get my fan to work

[janus]

Hi folks,

FINALLY my 92 T1 Tona is back on the road :) there's just one problem, the radiator fan won't come on. at first i suspected my hacked up wiring because the fan (it's a TII rad/ic fan) didn't have a connector, i got it with just 2 wire stubs sticking out so i had to wire it up to the existing fan connector in the engine harness. anyways, i tried the fan directly fed by battery and it worked, so the fan motor is not dead. next thing i did was trigger the fan ON by unplugging the CTS with the engine running but nothing except a short bump in idle rpm happened. i also tested the fan relay by swapping it with the A/C relay, still no change.

the fan connector in the engine harness has a black (GND) and a light green wire, which is going to the fan relay. ground was tested good. can't think of anything else than the wires to the relay or ECU, or some blown fuse. i forgot to mention that when i tried the first time by pulling the CTS there was a spark at the fan connector and a short movement by the motor, that was all i ever got out of it save for hooking it up to the battery for testing.

any suggestions or hints?
btw, does the ECU still close the fan relay circuit if it notices that no load is applied (electrical load like when the fan is on)?

[NAJ]

There are 2 power feeds into the relay, controller ground and output to the fan motor.
The ground for the fan motor is external.
Remove the relay from the PDC and check that both power sources are present with the key on.
If both are not present repair the affected power feed circuit.
With the fan connected use a jumper and jump from one power source to the fan output in the PDC, does the fan run?
If not either there is an open in the feed wire or your fan motor ground is faulty.
Check continuity from the fan output terminal to the fan motor and if ok check the ground.
If the fan does run when you jump power to output the problem is a bad relay or the ground circuit from the controller to the PDC.

[janus]

Jan, thanks a lot for your professional advice :) i will try to test all the cases you have posted. what i would need though is an internal circuit diagram of the relays used for AC/Fan/Inj/Fuel Pump or at least know at which pins of the relay socket the feed is at and which pins to test. thanks in advance!
i took it to work today and yesterday, it's about 2 or 3 miles through town (no real busy roads there) and 16 miles autobahn. so the 80 mph cruise will hold it in the center third of the temperature gauge just fine man, i totally forgot how awesome TD's are!

[NAJ]

I will give you the full system wiring for your car but I cannot gaurantee how detailed the relay schematics will be.
the wiring is from Mitchell.
There is another member who needs the wiring for his vehicle, 92 Daytona 2.5L T-1 so once I get them scanned and uploaded you will have them.
I may post them in his thread so I will let you know where to go to print them out.

[janus]

wow thanks a lot, but i actually do have a 92 wiring FSM myself! i have already looked at the wiring schema above before posting this thread. i just couldn't find any circuit diagram for the relays..

[NAJ]

If your 92 FSM's are layed out like my 90 FSM's they are not user friendly.
They will show all of the relays with a pinout but only show the circuit # and wire color going to the relay and you have to look at different sheet #'s to determine exactly where each wire is coming from or going to.
Usually all I do with relays is turn the key on and verify 2 power sources are present, if so an ohmmeter will tell you which is the output to the fan motor and the other would be the ground.
Like I said, I am gong to post the Mitchell wiring anyway so maybe it will help.

[janus]

yeah, exactly, pretty user unfriendly.. i will take some time and play around with my multimeter tonight and check those relay contacts in the PDC.
can i also try to jumper the switched batt+ pin (feeding the fan motor from the relay in the PDC) to direct batt+ to see if the connections from PDC to fan are okay?
also are there any fuses/fusibles i should check?

[NAJ]

According to the wiring diagram your 2 power feeds are the DB/WT wire(term 1) and GY wire (term 2).
The control side ground to the controller is the DB/PK wire (term 3).
The output to the fan motor is the LG wire (term 4)
Just turn the key on and with a 12 volt test light connected to ground check for 2 power sources, if they are present use a jumper from term 1 or 2 to terminal 4 and see if power is present at the fan motor connector LG wire.

[NAJ]

The wiring for your vehicle is posted in a thread titled 92 IROC 2.5 intermittant power loss to computer?

[janus]

thanks guys, i got it figured out. it was an issue of a blown 40A fuse and my hacked up wiring as originally suspected the problem was i didn't know there was a fuse for the fan feed or which fuse it would be.. some tedious FSM study and some hours of working the multimeter in the rain (my garage drive was blocked ) finally tracked it down. thanks for the help!