Thermo/Cooling Fan Not Working?

[dashdown98]

Hey guys, I have a VP V6 and the thermo fan isn't working. I'm not an electronic whiz so hopefully someone can help me. When I got it, the fan was hooked up to a switch in the cabin because it wouldn't work, but I realised they had put a 4 pin relay where a 5 pin should be. (Cabin fan didn't work either until I changed the relay). I disconnected the switch for the thermo and hooked it back up to the stock plug and then let the engine heat up to 3/4 but it didn't kick in. I was wondering if they had to put a bypass on the relay for the switch to work? Or maybe the sensor that turns the fan on (can't remember the name) is stuffed? Could be something completely different but I don't know. Cheers.

 

[Geek2.0]

I'm unsure about the relays or the modifications done by the previous owner, however, i can give you some information about the sensor.
There are two sensors in the VP, there is a coolant temperature sensor and a coolant temperature sender. The sender gives a signal to the dash, and the sensor gives a signal to the ECU, the ECU then controls the radiator fan. Under normal conditions the fan should come on at approximately half way on the gauge.

If it were me I'd probably just replace both sensors so you could eliminate them from being a potential problem. My sender was busted a few years back and the gauge was reading very high, but at the time I didn't know if the car was overheating or if the gauge was wrong.

If you do choose to go this route, both sensors are behind the alternator and are very easy to replace:

Disconnect negative battery terminal (important, the alternator wiring is not fused and runs straight to the battery)
Disconnect belt (noting how it goes on)
Remove drivers side alternator bolt
Crack passenger side bolt loose
Swing alternator up
Replace the two sensors (have a drain pan underneath to catch the coolant)
Reassemble everything
top off and bleed cooling system


When I did this the two sensors were cheaper at Holden than they were from Repco.

More info:
http://forums.justcommodores.com.au...8-1993/209877-thermo-fans-cutting-late-2.html

Good luck!

 

[FXST01]

Confirm that the fan actually works.

 

[hi_ryder]

^^^this

touch some direct battery power to your fan, make sure its not burnt out... then continue on with the rest.

 

[VPRob]

Does the fan come on when you turn the aircon on? It should. Unless your aircon is like mine and needs the dash out before it will work again!

 

[dashdown98]

Cheers guys. I should have specified, yes the fan does work - it was the first thing I checked. It's just not kicking in when the engine heats up. I had a play around with it the other day and I couldn't get it to work so I hooked it back up to a switch again. I checked everything with a test light and neither the AC relay nor the Thermo relay are getting power that I could see but if the switch annoys me too much I'll try the sender and sensor. I don't mind having control over the fan anyway it's just that if anyone else drives the car they might overheat it. Thanks again!

 

[hi_ryder]

prob just a dead sensor...

 

[HarryHoudini]

prob just a dead sensor...

Yeah,isn't there another Thread on here that pointed to one of the 2 water Temp. senders failing.

 

[hi_ryder]

should be a 2 wire temp sensor just under the alternator screwed into the inlet manifold, that will be your ecu temp sensor. sounds like it might be cooked...