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E-Fan won't kick on!


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The fan is still good, I checked it with a 12v source.

It won't come on with the temp. switch or the A/C.

Also I just put a new relay for for the fan in.

 

Any guesses...or hopefully knows lol?

 

Thanks!

-Cody

 

Oh yeah

91 2wd 4.0 automatic....has a 96 Grand cherokee 4.0 if that makes any difference

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It should still kick on when it gets hot even though the A/C isn't charged. My 91 aux fan doesn't kick in off the sensor until 230* or so on the temp gauge. So I wired in a spare dash switch I had to kick it on if it didn't.

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  • 2 weeks later...

not much left on the list .

 

Confirm circulation in the heater core . Compare temps to the in and outlet hoses by touch , careful , it's hot .

 

Air lock , did you burp the system well enough ?

 

Faulty temp sending switch .

 

Water pump

 

Head gasket , but your not mentioning any symptoms such as oil in the AF , milky oil , extra steamy exhaust or disappearing coolant

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Any chance you replaced the water pump and got one for a 4.2L engine by mistake? The 4.2L used conventional vee belts and the water pump rotates the opposite direction -- but the housing bolt pattern is the same so it WILL bolt right onto a 4.0L engine. With the impeller blades pitched the wrong way, it can't create much flow.

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Okay so I said f the factory swith and wired in two 10" fans and put a new radiator and a new thermostat.....why is this thing still rinning hot??

 

How hot are we talking about? Boiling over hot? What's the temp gauge reading? When does it get hot; in traffic or on the freeway? Have you verified the indicated gauge temp with an independent source (i.e. handheld laser or infrared thermometer)? The dash temp gauge isn't exactly a precision instrument.

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Boiling over hot...and usually when I've got a lot of strain on it. Also i don't think i have the 4.2 water pump. Also i saw that the heater cntrol valve was unhooked and i hooked that back up and its doing a lot better but i haven't put a whole lot of stress on her and it was kind of cooler when i took a drive....around 88 instead of 98

O

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In that case, are you still running the original catalytic converter? I replaced basically the entire cooling system when I had the stock engine but still boiled over especially going up long grades in the heat. Turned out to be a restricted / clogged cat. Put a "test" pipe on and problem solved on my 91.

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