Fan Solenoid replacement

[Dpas1973]

Well now the line pressurizes, pumps up and in doing so... SHOULD SEE the fan free wheel, or pull the plug and fan locks up.

Something is dicked up or you not seeing it, feeling it... cuz that's one of the quickie test. LOL

For fan to cycle, thermo switch is the part doing the business. It opens the circuit at +/- 225 and on comes the fan. if one as voltage at the switch? With a cold engine or connected together, making it to the TDM and out to the valve. Loss of voltage or a break in any wire... FAN will NOT run free. For whatever the reason this process confuses the poop out of many.

Watch out for those "packard connectors" maybe or could be an open circuit in one. This is why the test light (cheap) or mulimeter is going to be your best-est buddy to follow the circuit. When you have a correct working system to play on , the pull this or pull that connector will make science sense.

Pull my finger and turn on the fan, CAMO

And now a couple of utube videos> Watch and learn. This is what you NEED to know in the driveway or on the trail.

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Ok I just jumped out the new fan drive switch and no change same think I connect the jumpers and the Cadillac valve pumps I disconnect jumper and it stops but no change or movement in fan


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[Dpas1973]

Ok I just jumped out the new fan drive switch and no change same think I connect the jumpers and the Cadillac valve pumps I disconnect jumper and it stops but no change or movement in fan


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Also I had 28v at the fan drive wires


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[REF]

Could the fan kick out switch on the injector pump be bad or sticking. that could prevent the fan from engaging . Sorry read the whole thread, now realize your running too cool, not a common problem with these trucks. My unit tested fine, fan came on and off when tested at idle but fan would not come on at speed. found the lever on the micro switch was bent so as soon as I mashed the throttle down to go the switch kept the fan from coming on.