jonnywalker

I've searched and searched but have yet to really find my dilemma.

I recently changed my lifters and put a new head cover gasket etc. in that process I replaced water pump, 180 degree thermostat, radiator. Flushed system. Fan clutch and thermostats coolant sensor. Jeep will drive fine barely getting to 210. Now, if I then the ac on here comes the issue. The electrical fan never turns on. I connected the fan directly to the battery and it does turn on. Checked all fuses and nothing. If I'm sitting with the ac in the temp will start increasing, the ac doesnt feel as cold and baam. 260 degrees.
Any ideas?

freegdr

Year ?

jonnywalker

1999 with 198,000 miles

freegdr

Did fan come on b4 as soon as ac was turned on b4 all parts were changed ?

jonnywalker

Yes it did.

freegdr

Do you still have old collant temp sensor ? Could be you got a bad one its all wired together with Ac circut.

jonnywalker

I thought that the old sensor was bad because I just changed it two hours ago.

md21722

Thermostat should be 195F.

Coolant temperature sensor in the head regulates the electric fan. Should come on by 220F.

High pressure switch for the A/C also regulates the electric fan. Should come on 280-320 psi and shut off at 235 psi. This switch also will switch off the clutch at high pressures, like 490 psi if the compressor over pressure valve doesn't pop first.

Fan relay OK ? Dash temp indicator reads OK? Fan connector is making good contact? I'm assuming the fan belt is on correctly and water pump is spinning in the right direction because without A/C it is working. Radiator may also be plugged up. If the flush released rust into the system it could have landed in the radiator.

freegdr

So it was not coming on so you replaced the sensor ? Is Ac compressor engaging ? Are ac pressure switchs plugged back in ?

Pelican

I believe coolant temp sensor for the '99 is in the thermostat housing.

djb383

.....and '99 efan turns on when the a/c clutch engages......not when a/c pressure reaches X psi.

jonnywalker

Normally if I'm not mistaken, when I turn the ac on , the fan should engage. Well it doesn't. The ac does engage and blows out cold air.

jonnywalker

Keep in mind that it only overheats when ac is on. Electric fan won't turn on at any temp even if I turn the ac on

djb383

Have u checked fuses and relays?

jonnywalker

Fuses yes relays no. I'm trying to search how to locate and test them