Over heating and electric fan won't come on

Ok heres the problem. The electric fan wont come on when the temp goes up. The e-fan will come on when I turn on the A/C.
I'ts a 96 4.0 auto with 250,XXX on the clock.
Recently I changed the cluster from idiot lights to gauges when i was replacing the temp senser I broke it off in the head. I could not get it out and it wasn't leaaking so I left well enough alone. I put the the senser in the T-stat housing.My question is would this be giving me a bad reading?

While driving the temp stays around 210 but when I slow down and or stop it starts to climb to the line right before red. It has not boiled over yet..
When I notice it getting hot I turn on the A/C and the temp will come down a few notches.

I changed the senser that was orringanly in the t-stat housing and there was no change.
Checked the relay in the fuse block and its good.

Im about to just wire it hot and let it run all the time (but I dont want to),

Please help.
Thanks

the e-fan thermo switch is in the radiator. the one in the thermostat housing is for the ECM.

Not true for the '96. Sensor for the ECM is in the thermostat housing. There is no separate "switch"/sensor for the efan. The ECM switches the efan. There have been several recent threads relating to the problem rogersjeep is having. I have the same symptom and am still waiting for someone to come up with the definitive answer to fix this. In the meantime the solution appears to be to install a switch or a variable control unit to automatically switch the fan on.

After driving in this morning to work I checked the temp with a temp gun
and when the gauge was reading about 215 the T-stat housing was reading about 185.
Is that a reliable way to check the temp?

Something may be wrong with your reading. The T-stat housing should be the hotest part of the engine since the heat generated in the engine increases as the water get closer to the out port to the radiator.

You need to replace the sensor in the T-stat housing with a good one. The ECM uses the reading from this sensor to determine engine temperature to set fuel delivery, ignition timing ect; ect. This reading is also used by the ECM to turn on the electric fan.

rogersjeep said:

While driving the temp stays around 210 but when I slow down and or stop it starts to climb to the line right before red. It has not boiled over yet..
When I notice it getting hot I turn on the A/C and the temp will come down a few notches.
Thanks

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This is a bad fan clutch, it's very common, and most people completely overlook it. That won't fix the electric fan problem, but if the fan clutch is working properly, the temps will not get that high in the first place. replace the clutch to stop the overheating, then you can concentrate on fixing the e-fan switch. (maybe the relay)

rogersjeep said:

Replaced the fan clutch about 6 months ago (sorry forgot to mention that).

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hmmmm... that type of overheating should not be happening then... there is definitely something else happening other than the e fan not coming on... I'd replace the temp switch/sensor again (they are cheap) you are right to make sure to double check that you are getting a true reading at the gauge.

Well guess its just my gauge that is way off.
I blocked the front of the radiator and let it idle for a while and the fan caome on.
the temp on the gauge was in the red.
But the temp with the temp gun was about 230 so i guess im good.
just need to figure out how to calibrate the gauge to the sender.