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Cooling fan problems

Posted: Wed Nov 11, 2020 7:23 pm
by M4rksc
Hello. Im looking for some advice from the community. I have a 1995(m reg) Ford probe 2.5 v6. Im experiencing a few problems with the cooling fans. Here's what happens. My LOW speed cooling fans dont switch on and therefore the temp creeps up until both HIGH speed fans come on and it sounds like a jumbo jet. On my other probe the low speed fan would come on regularly and keep the temps constant. So far I have replaced the engine temp sensor by the dipstick. When I unplug this sensor both fans come on full power. I have also tested each of the 2 fans directly with a 12 v battery and both speeds work as they should. Ive reached a dead end with the relays. I know it has them for the fans but dont know how many and which is for what. My haynes manual shows a total of 6 but I dont know if thats right or not. I have identified 2 relays which both click on when the 2 fans go on full speed. If anybody could shine some light on this I would be grateful. Thanks!

Re: Cooling fan problems

Posted: Thu Nov 12, 2020 10:41 am
by mojo98
Forget your Haynes manual, it's OK for some things but can't believe everything in it.
There is access to electric diagrams in the Oracle, but believe you may have to be a full member to gain access to the Oracle (at a cost of £10 per year).

But in the mean time there is only 2 relays, low speed and high speed, and some fuses,

I would suspect that you may have a faulty low speed relay.

Re: Cooling fan problems

Posted: Thu Nov 12, 2020 12:13 pm
by jrh
One fan for engine , the other fan is for air conditioning system.
Each fan has two relays, one for low speed , the other for high speed.
There are TWO engine coolant sensors, one for temp gauge , one for the two low/high speed relays of both systems.
The relays are driven by predetermined settings in the ECU/PCM.
As Mojo wrote, throw the book of lies on the fire, join the club.

Re: Cooling fan problems

Posted: Tue Nov 17, 2020 9:08 pm
by M4rksc
I have finally found the problem. It turns out I have a broken signal wire from the ECU to the low speed relay which is located behind the front bumper. I will trace it back as far as possible. If I cant find the break I will run a fresh wire over.

Re: Cooling fan problems

Posted: Tue Nov 17, 2020 10:25 pm
by Kit
Well done :o

Kit