ive got a problem, i just bought a mehcanical coolant tempature gauge, and dont have any free ports on the engine to put it in. i did put it in in place of the fan switch, the sender on the block, and it worked but i had no fan, :-(
i was thinking about just rigging up a switch for the fan relay using the stock green wire from the fan tempature switch, but having lost my multimeter, i dont know the polarity of the unit. seeing how i am on no funds for another week, what can you all suggest? i kinda need that gauge cause all i got is an idiot light. thanks,
Nemo
if you put in an aftermarket gauge, no point in keeping the stock gauge hooked up. locate the single wire sending unit and pull it out for your aftermarket gauge. if your car had the dummy light, it will still be a 1 wire sending unit.
do not remove the 2 wire sending unit whatever you do. that is your temp signal for the ecm. without it, your tuning will be out to lunch as the ecm thinks the coolant is -40F. this also sends the signal for the ecm to controll the fan.
sharkey wrote:do not remove the 2 wire sending unit whatever you do. that is your temp signal for the ecm. without it, your tuning will be out to lunch as the ecm thinks the coolant is -40F. this also sends the signal for the ecm to controll the fan.
where/what is the 2 wires ?
well, i guess i forgot to tell you that it is a 2.2 ohv 1990 cavalier. i removed the one wire green sender and installed the sunpro mech. sender and the fan did not turn on. wait,..... i checked it with the ac off........ the gauged read above 190 so i pulled over and turned the ac off, and no fan. after that at my house i was reading about 200 degrees and stil no fan. so i put the sender with the single green wire and then i got fan with the ac on.
now i am operating on the princple that the one wire sender is a switch, i figure that the block is grounded, negative, and that wire goes to the relay for the fan. the haynes manual says that there are two senders, one for the ecu and one for the fan. so i am thinking that i could just ground the green wire to the block and i did that for less than a second buit no fan. poop. well what i am thinking is that i could hook up a switch to the wire and go from there, But i essentialy did that when i grounded the green wire to the block and the neg. terminal on the battery, but again for less that a second, just a touch. well thats where i am at now, thanks for the support and i hope that in this experance i can pass on what i learn to others. thanks,
nemo
Have you looked in the Haynes book for the diagram page titled "1987thru 1992 air conditioning system"?
That's where the wiring diagram for the Coolant Fan circuit is listed with the two wire (Yellow and Black) Coolant Temperature Sensor feeding into the ECM.
The Gauge or Light Sender is shown in the Diagram "Typical Gauges, indicators and warning system" pages 12-30 and 12-34 in my "1982 thru 1984" book.
I think grounding the Green wire to the block would only cause the Gauge to read zero or low temp or the temp warning light to illuminate (If that is what's fitted).
Hope this helps
Alont
having read the haynes manual,(i thought i had that one, but all i had is 2 different chilton manuals) i learned 2 things, (1) the car operates at 195 degrees and (2) the single green wire sender is for the guages. now if i had checked the car with the ac on, i would have seen this. also if i had checked the temp light when i gounded the sender i would have seen the light come on. well you have been a great help. thanks and all this DID help. thanks,
nemo
