Cooling fan question

[84 SVO Luvr]

Hello everyone, I have a cooling that will run if I hook it direct to the battery, but won`t tun on on its own. I have changed most of the sensors, and the relay under the dash, is thei anything else that would keep it from coming on, on its own? Thanks for your time!!!

[SVOeric]

You should check that you have power coming to the relay under the dash. You said you changed the relay, you mean the black box with TRW stamped on it ?

[brown7]

The three parts of the fan system are the fan, temp switch, and the fan control module/trw box.


1) If the fan works with direct voltage-fan is good
2) if the fan works when the trw box has two wires jumped-box is good.( I don't remember which two I jumped, I think I either guessed or had it written down at the time)
3) Temp Switch is not likely to go bad.

I thought my box was bad because my fan never came on. Did the above and everything checked out. Turns out I never ran my car hot enough to turn it on, leaving it running it would come on about -L-a and turn off once it hit -M-

[blueboss]

Hello everyone, I have a cooling that will run if I hook it direct to the battery, but won`t tun on on its own. I have changed most of the sensors, and the relay under the dash, is thei anything else that would keep it from coming on, on its own? Thanks for your time!!!

Let's keep this simple. Remove the wire from your cooling fan switch located on the lower intake. Now ground the wire. Two things should happen in rapid succession. 1. Your fan module under your dash should click. 2. Your cooling fan should come on. If these two events occur, your cooling fan switch is malfunctioning. If your fan module does not click, there is either a wiring problem to the module, a power delivery problem to/from the module or the module is defective. If your cooling fan does not come on, you have either a wiring problem or a faulty fan module. It is possible that you believe the fan should activate at a predetermined position on the temperature gauge and it is not. The factory gauges are inaccurate and they should be treated more as a guideline rather than a precision measuring instrument.

[SVOeric]

He said he replaced the TRW box, and the sensor, which is why I went with, see if there is power to the box.

[84 SVO Luvr]

Eric, Brown7, and BlueBoss, thanks for all the tips and help AND for your time, all the wiring is not my cup of tea so i`ll be sending the car in for the help it needs, thanks again!!!!

[blueboss]

He said he replaced the TRW box, and the sensor, which is why I went with, see if there is power to the box.

Didn't say you were right or wrong. I simply thought it more productive to give the poster a general overview of common failure points within the circuit and tell him what to check to ensure the circuit is operating properly. Give a man fish, feed him for a day. Show a man how to fish, feed him for life. If he learns how to do it himself, perhaps one day he can pass on what he's learned to someone else.

[SVOeric]

Thought I was going the same place... start at the begining, and work your way to through the system til you find the problem.

[84 SVO Luvr]

Didn't say you were right or wrong. I simply thought it more productive to give the poster a general overview of common failure points within the circuit and tell him what to check to ensure the circuit is operating properly. Give a man fish, feed him for a day. Show a man how to fish, feed him for life. If he learns how to do it himself, perhaps one day he can pass on what he's learned to someone else.

Thought I was going the same place... start at the begining, and work your way to through the system til you find the problem.
__________________
Eric C
SVOCA Webmaster

Thanks to you both, I`m going try to fix it myself instead of taking it in, like I said i`m no electrical guru or anything, but thanks to you guys, I have all the info I need!!!!