Why am I getting a constant signal out of my fan switch? I bought a new one and that gives me the same so am i miss the plot here. I was under the impression that as the switch warms up the contact is then made!! and luss the fan starts!!!
The Sierra one on my Raceline water rail is O/C untill hot then closes and completes the circuit, I'll have a look at the wiring diagrams for the zetec when I get home....
The fan switch will only switch on once the coolant reaches a set temperature and then go off at another set temperature. Not sure what signal you are trying to measure but would think you should be looking for continuity once the coolant reaches the set temperature
how are you measuing this "constant signal"
1. remove or isolate swithc from carthere should be
2. there will be one or two contacts.
3. measure resisitance between each contact and body of switch and report back. (body is usally earth contact).
quote:
Originally posted by robocog
Thought the Zetec used 2 temp sensors on the thermostat housing that when the ECU detects a certain temperature the ECU turns the fan on ?
Temp sensors = different resistances at different temperatures
There is one at the top - this as far as I understand is the temp sensor for ECU and the one at the side (under the hose outlets) for the dash gauge
[Edited on 31/7/08 by robocog]
I couldnt get my original zetec fan switch to work so i used one in the polo rad.
Im sure iv got it to swtich the earth not the feed.
If theres continuity through it all the time when disconnected its gotta be a dodgey switch. It should on have continuity through it when its at the
operating temp.
quote:
Originally posted by Paul TigerB6
quote:
Originally posted by robocog
Thought the Zetec used 2 temp sensors on the thermostat housing that when the ECU detects a certain temperature the ECU turns the fan on ?
Temp sensors = different resistances at different temperatures
There is one at the top - this as far as I understand is the temp sensor for ECU and the one at the side (under the hose outlets) for the dash gauge
[Edited on 31/7/08 by robocog]
The above is 100% correct as fitted to the original donor car with the top sensor feeding the original Ford ECU.