Engine Fans Not Playing.

[swindorski46]

The engine fans on my '97 4.2 aren't cutting in at all.

I've checked fuse numbers 1 + 3 in the boot, and both relays are in place.

Is there a way to check the relays are Ok or should I be looking elsewhere?

[dannylt]

How do you know they're not coming on? Don't trust that temperature gauge! If you have close access to a dealer, you can see what the ECU thinks the engine temperature is - think it cuts in around 85. By which point the gauge could be reading 100!

[swindorski46]

I've stood and watched them with the bonnet open. The gauge has spun round to 110+ and they still don't move.

Surely that's not right?

[shpub]

Normal problem is the ECU temp sensor contacts going dodgy. Remove the plug and the fans should come on straight away when the ignition is switched on. If not the fault is somewhere with fuses/relay/wiring. Sensor is located under the front engine cover.

[crazycats]

Possibly the temperature sensor.....I'll leave it to someone else to tell you where it lives, probably in the rad somewhere.

It may be worth locating it and shorting it out, if your fans run then its the sensor, if not then the problem lies with the fans...however its unlikely that both won't work all of a sudden.

There's probably a control box lurking in the nether regions of your car somewhere....again not sure, however I'm sure someone on here knows

To be continued.......................

[ron.v]

I had same prob couple of weeks back it was the terminal blocks at the bottem of the centre of the fans a pull apart and a good spraying of the old W.D.40 did the trick.
hope this helps
P.S mine come on about 100 then knock it down about 10-15 degrees.

RON

[RZD]

It does sound like it's the temp sensor which is located below the shaped glassfibre panel between the fans and the engine.
The panel is held in place by 6 (I think) hex-screws and is easy to remove although you will have to loosen some hoses and the air intake ducts first.
The sensor costs about £15, and is just screwed into place.
Hope this helps.

Leszek

[k-9]

The easiest solution is to check the connectors for the power to the fans, they get corroded as they sit in the open normally under the fans. Mine did the same, got out the old wire brush, and it all worked a treat.

[swindorski46]

Spot on K-9. Dodgy connections on the cables.

I checked that power was getting to the last connection, re fitted it with a new one and hey presto.

Good job it was that really, I couldn't find any sensors!!

[ron.v]

errr!!!!! i think thats what i was trying to say 3 posts earlier

ron

[swindorski46]

Sorry Ron!

Not sure what terminal blocks are? You threw me with your technical jargon!!!

Anyway I fixed it at lunchtime today so you definately steered me in the right direction.

Thanks.

[vroom]

Good luck with lucky 7!

Don't worry about the fans too much. I had the same concern. Would often get 110 deg on the guage with no fans cutting in. Only after connecting the ECU to my laptop did I notice there was about 10-15 deg difference between the coolant temperature (used by the ECU to control the fans) and what was shown on the dial.

Checked that the fan came on at around 95 deg and all was OK.

Nick.

[kevin63]

Try taking the plug apart and cleaning it as i did this and found that someone had put vasalene in the plug before they conected them together and so no power to the fans. The plug was on the wire right next to the fans themselves on the thick wires.

[tweety]

Had same problem with sensor, but when plug taken off both old and new sensors still only passenger side one comes on, both fuses and relays checked ok. At least pax one now cuts in at 95 degrees. Anyway should both come on with plug removed for 96/P 4.2 and any further ideas ?

Cheers, Al.

[shpub]

Both should come on when the sensor plug is removed.
If only one comes on... most likley problem is the fan power connectors. Swap them over to see if the other fan comes on. If so the power connector (or fuse/relay is duff). If the original fan doesn't come on, most likely the fan is duff.

I've just replaced the terminal connectors and then wrapped them with self-amalgamating tape to make them water proof.

Steve