[Timelord]

Hi,
I have a 1998 Ford Escort 1.8 Zetec with A/C and the
tempgauge gets 3/4 high when stationary with A/C off.
I changed the radiator fan switch which is an 86C/100C
dual switch. I suspect the first radiator fan speed is
not working as when I short out two pins the fan runs.
Current is about 1A through the switch. Worrying bit is
there is no voltage detectable on the second contact wires, as opposed to 12V and 0V on the first contact.
Is this normal or does it indicate a duff PCM? With an Ohm-meter I get resistances to 0V on these second contact wires of about 3kohms and 5kohms.
I really expect a voltage as otherwise the PCM cannot detect whether the switch is open or not.
Or is there a relay on this circuit which is defective?
Haynes manual doesn't have the wiring diagram ;-(

[Hometune]

The coolant blower relay is behind the battery.

[Timelord]

Hi,
Many thanks for that mega-swift reply.
I have just discovered something behind the battery!

Now am I correct in assuming there are two relays
viz. one for full speed and one for half speed?
Or does the one unit have two internal relays?
Sorry to keep asking silly questions!
I have checked out the thermoswitch and both contacts do switch.
Al

[Hometune]

I'd guess its a 2 speed relay. If you pull it out, and count the pins it will give you an idea. If it has just 4 (2 small and 2 large) it is a simple relay.
If it has 6, 7 or more or is double sized then I'd think it was a 2 speed unit. Try one from a scrapyard, it will be cheap. :D

[Timelord]

Hi,
I have managed to find and download a circuit which shows 3 relays: The main one which is always on except when the starter motor runs, and it is followed by a high-speed relay and then a low-speed relay.
The latter relay coils go to PCM pins 31 and 35.
Unfortunately no mention of the thermoswitches in this.images/smilies/frown.gif
:(
2006-08-27_145537_Cooling_fans_95_Escort.gif
The relay behind the battery looks hard to remove.
Do I have to take off the wipers and grill under the wipers?
Regards,
Al

[Timelord]

Hi,
There are two 'relays' behind the battery: one is green and the other grey. They have 5 and 6 wires. I opened one up and it is not a realy as God intended viz coil and contacts, but has coil, contacts, 8-pin IC, 2 1Amp diodes 3 capacitors and 4 resistors.
Pressing the relay does not make the fan run but current
of a few amps goes somewhere.

Does anyone have a wiring diagram of the fan wiring?
The fan has two thick wires on the back on two on the lower side. Does anyone know why a fan has 4 wires?
Thanks.