electric fan problems

My electric fan runs constantly....I dont know why but it causes a huge drop in my battery power. So disconnected it for a while, reconnected it today and it still runs constantly. Why is that, My temp is fine.?

Possibly bad sensor in radiator? Also fan comes on when a/c is activated. May be in that circuit somewhere? Two possible things to check.

Theirs sensors in the radiator??

My 88 does, so I suppose your 89 does also. Sometime in the early 90's they put it in the thermostat housing. Look on the drivers side of the radiator for a sensor about half way down the side of the radiator. It will have two wires, I believe, coming off of it and there will be a connector close by that you can disconnect.

Oh yeah I know what your talking about. I don't think thats it. Does it make sense my jeep is noticeably faster with the fan on?

Disconnect the fan switch on the radiator from the harness and see if it still runs continually. If it does, try pulling the AC relay to see if it's contacts are stuck. You could also try swapping the fan relay with a known good relay.

Fred

I looked in my 88 XJ electrical troubleshooting manual about the electrical fan operation. There are two ways to turn on the fan. The first one is when the temp sensor in the radiator measures 190F in the radiator, the second is when the AC clutch engages.

For the temp sensor operation the Temp sensor in the radiator is really a switch that closes when 190F is measured AND then the Cooling Fan relay is turned on and sends power to the fan.

For the AC system to turn it on the Cooling fan the AC Clutch relay is engaged, then voltage is sent to the Cooling Fan relay which in turn turns on the Cooling fan. According to the schematic if the AC clutch is engaged then the electric fan will run. Inspect your AC clutch to see if it is engaged ALL the time or it engages then releases. If the clutch disengages then I'd rule out the AC clutch relay.

I would pull out the cooling fan relay and replace it with a new relay. You will find the relay on the driver's fender near the air filter box. It there all alone so it easy to find. Also you may want to consider pulling the relay out to keep it from running down your battery until you find the fix. With the engine cold you could use a ohm meter and determine if the switch in the radiator is open or closed. If it is closed then replace the switch. You will have to drain the radiator to change it. If it the factory radiator you might be better off installing a new radiator and install a new sensor.

I used a lit LED switch and two relays for my electric fan on my '92. Use the first relay to switch the second on to activate the fan. Two relays prevent resistance due to heat. Your fan will perform better than ever and the wires won't overheat at their connections. The light reminds you to kill it if your stereo is on.
SWITCH PANEL: I used the piece the clock is housed in to install the switche(s). There's enough room behind it for insulated terminals on the switch.

three weeks ago, I had a new motor thrown in the 89, and a few other issues taken care of, including the completion of a 92 style cooling system I started a while back. when they got the motor in, they threw int he thermostat at the front of the block, and it now turns on at 190 and never shuts off. They were pretty sure it was because the tstat had a low shut off point, and it was never getting that cool... but with the fan on, it runs consistantly below 210, and I don't notice any low battery...

previously, I had the fan on a switch, that I mounted under the dash. it was lit, so I always knew when it was on or off... and honestly, it took more work, but I liked that. the hardest part was running the wire through the firewall.

I've never heard the ac clutch theory, I'm going to check that out next chance I get. would that relay setup be on an 89? I changed the radiator/coolant bottle set up, but no wiring.

1989laredoxj said:

My electric fan runs constantly....I dont know why but it causes a huge drop in my battery power. So disconnected it for a while, reconnected it today and it still runs constantly. Why is that, My temp is fine.?

Click to expand...

Since it also runs constantly when you switch on the A/C, I'll bet that the contacts of the fan relay are stuck. Try a new relay.

i have the opposite problem my fan never turns on. not even with the a/c on. any suggestions for me?

fan relay. Im a newb