I have a 89 Ford F150 4X4 with a 4.9l 6 cyl. engine and 4 speed manual trans. Recently my temperature gauge stopped working and after a while I noticed that my cooling fan stopped coming on too. I have been having problems with overheating, replaced a a hose and fixed pin hole in radiator. Then I replaced the temperature sensor on the front of the motor but still no gauge or fan. Checked the gauge with a power supply and it worked but have no idea where to start to check fan or what meter readings should be. Any help on this would be greatly appreciated.
Thanks Booboo
(Barb)
some ideas: (I don't know much about your car, so I'm going by the similar problems that I'm having with mine)
1. On my car, I have 2 fans....a condensor fan and a radiator fan. One of the first things I did was unplug the fans' harnesses, and jumped the wires in the plug to 12v+ and ground to see if the fan turned on. Since both fans turned on, I knew that they were ok (and their motor was ok).
2. Right next to the thermostat housing on my engine, there's an "Engine Coolant Temperature Sending Unit" with a plug on it. I was told to disconnect the plug and ground it. Then, put the key in the ignition, and turn it to ON (not the car running, though), and see if the gauge moves up to HOT. In my case, the gauge shot up very fast. I was told to shut off the ignition before it got all the way up because it could hurt the gauge. In my case, it happened too fast, but at least I knew the gauge was working.
3. The condensor fan had two relays (well, there were 2 relays by it), and the radiator fan had 1 relay. ANother test I was told was to unplug and test the relays. There were four terminals on the relays....A, B, C, and D. I was told to check for continuity between C and D; it should have continuity. Then, I was told to give C and D power and ground, and then A and B should have continuity. Well, all three relays failed the first test, but all three of them passed the second test (with the power and ground).
I was also told you can check the wires that were going to the relays (for power and stuff like that), but I never got to it.
4. Simple suggestion: Check the fluid in the reservoir. Mine was fine.
5. My problem is a little different from yours. My car is overcooling. In other words, my fan doesn't like to turn off....even when I turn off the car. Sometimes it even kills my battery. The next thing I've been told to check is the Fan Timer. I'm not sure if you car has one, but mine does....and it's $150!! I might test mine first before I buy a new one.
6. Finally, You also might need a new thermostat. I bought a new one, but haven't replaced it yet. Yours might be stuck open (or closed....I forget which is which).
Remember, if your car starts overheating, you can combat it by turning on your heat full blast....although it must be tough if your temp gauge isnt working.
Good luck.....write back with questions, or just to say where you are:-)