95 850 No Cooling Fan

Post by **polskamafia mjl** » 19 Jun 2015, 14:15

The radiator fan has stopped working ever since I completed an M56 swap. I unplugged the middle connetor on the fan relay and ran a jumper wire from the negative battery terminal to both pins (one at a time). Ground either pin does nothing although I hear a buzzing or clicking on one of the pins.

I'm not sure where to go from there. Does that indicate the relay is bad or that something else is wrong?

Post by **Ozark Lee** » 19 Jun 2015, 17:13

Did the third smaller wire with the large lug get hooked back up with the other two large wires on the starter? All three go to the same lug and that smaller wire provides power to the cooling fan relay. If it is hooked up at the starter check for battery voltage on the red wire on the cooling fan relay. Voltage should be there in any key position including key off.

...Lee

Post by **tryingbe** » 19 Jun 2015, 20:36

Trace the big red fan wire.

Post by **Ozark Lee** » 19 Jun 2015, 23:01

tryingbe wrote:Trace the big red fan wire.

Big and small are relative. Compared to the battery cable and the alternator cable where it terminates it is small. Compared to the other wires on the fan relay it is big but it is the same wire.

...Lee

Post by **abscate** » 20 Jun 2015, 04:29

A picture here could put aside relative references..anyone had there starter wiring apart recently?

Post by **polskamafia mjl** » 20 Jun 2015, 13:46

I've got all 3 wires hooked up to the same stud on the starter. I'm color blind so I'm not certain which one is red but I checked for voltage at all 3 of the large wires on the fan relay. None of them had voltage.

: Fan Relay Wiring.jpg (111.84 KiB) Viewed 1127 times

I unplugged the connectors and checked the voltage inside on the metal contacts.

: Fan Relay Wiring @ Starter_2.jpg (124.29 KiB) Viewed 1127 times

Hard to see but all 3 starter wires are hooked up there.

Post by **Ozark Lee** » 20 Jun 2015, 14:08

You should have battery voltage on the single wire in its own connector, to the left in the picture (that wire is red). It looks like it is hooked up correctly at the other end on the starter.

That wire has a "Fusible Link" which much have popped open at some point. The fusible link is actually made into the wire and it looks like a fat spot in it but I'm not sure where that link is located along the path of the wire.

S.O.P. is to replace the wire if the link opens but you may be able to splice a new link in if you can find one. I'm not sure what amperage it should be and that is one of the things they would need to know at the auto parts store to sell you one. My guess is that it is in the 30 to 40 amp range but that is only a guess.

The other much more dangerous way to get the fan to work again is cut the link out and splice around it but that could, under the wrong circumstances, cause the car to catch fire. Some of them have burned even with the link in place.

...Lee

Post by **Ozark Lee** » 20 Jun 2015, 14:10

You should have battery voltage on the single wire in its own connector, to the left in the picture (that wire is red). From the lower picture it almost looks like the wire is bolted to the case rather than the stud along with the battery and alternator cable. Double check that.

...Lee

Post by **polskamafia mjl** » 20 Jun 2015, 14:45

A better view of the starter wiring and the stud. I double checked it but everything looks ok to me. The two large wires are on the stud and the smaller wire is certainly on it as well.

: Starter Wiring.jpg (163.62 KiB) Viewed 1122 times

: Starter Wiring 2.jpg (139.43 KiB) Viewed 1122 times

I think my cheap little multi meter is going to crap. After messing with it for a little I got battery voltage at the left most connector.

: Fan Relay Voltage.jpg (158.77 KiB) Viewed 1122 times

With voltage at that wire that should mean the fusible link is still intact, correct?

Post by **Ozark Lee** » 20 Jun 2015, 15:07

You are good to the relay, the fusible link is OK, and the arrow obscured what you were bolted to in the first picture - everything is fine at the starter.

With the single wire connector and the two wire connector at the opposite end of the relay both plugged in (the two connectors that were unplugged in the original picture) remove the center connector and, one at a time, ground each of the two pins on the relay. One should start the fan in low speed and the other should trigger high speed. I won't try to tell you colors so as to not frustrate you.

If grounding the pins doesn't work on both (or either) fan speeds the relay is likely bad but the fan could also be bad. If the relay clicks when you ground the pins I wold start to focus on the fan. You can test it by running a wire from the battery to the fan terminals individually. It should be a fairly large wire, like a lamp cord.

If both speeds work when you ground the relay pins then something is amiss with the wiring from the ECU to the relay.

...Lee