96 XJ repairs itself? Strange stuff with aux fan/"low washer" light

stock 96 XJ sport 4.0 HO, 290,000 miles

I was under the impression that my auxiliary fan wasn't working when I bought the XJ at 253,000 miles spring of last year. I had to replace the temperature sending unit and the temperature sensor first thing. When it got hot out I figured out that I needed a new fan clutch. I've seen the temperature gauge almost into the red and the aux fan had not turned on either. My mechanic bridged the aux fan relay into the fuel pump relay so it would run at all times so I knew the fan worked. I had the fan clutch replaced a few days later and unhooked the wire between the fan relay and the fuel pump relay. The XJ got a little hot many times over the summer but the aux fan never came on.

A few days ago (and at least 30,000 miles since the replaced fan clutch) my aux fan starts coming on like it's supposed to. The temp gauge doesn't even reach the last white mark before the red and it comes on. I'm baffled.

Today my "low washer" light came on for the first time ever. I've ran the washer fluid tank dry countless times and it has never came on. I stopped and got a jug of fluid. When I popped the hood I was expecting to see a bone dry tank but it was almost one third full. I filled it up anyway but the light hasn't gone off. This too, is strange.

I'm not looking for an answer here really. Just thought I'd put it out there to see if anyone else has had this happen. I'm hoping the computer isn't going haywire. The Jeep runs exceptionally well aside from not having over drive.

Relays can be iffy. Maybe an iffy relay or some sort of poor connection for the fan relay? It won't hurt anything to pull the relay and look closely at the contacts, discoloration may be tip off.

As far as the coolant level low indicator, mine would light every time the reservoir got below half. If I filled the reservoir all the way, the fluid would splash out of the cap (poor seal). I cut the wire for the coolant level indicator as I got tired of looking at the light .

You might want to check the grounds next to your ECM. I stripped back a little wire and did an ohm test from the wire directly to my battery negative. The issue was the ground loops on the wire and corrosion. I replaced the ground loops and soldered them on there. This is the (eventual) ground for your fan relay, likely some of the instrumentation and likely many other important things.

8Mud said:

Relays can be iffy. Maybe an iffy relay or some sort of poor connection for the fan relay? It won't hurt anything to pull the relay and look closely at the contacts, discoloration may be tip off.

As far as the coolant level low indicator, mine would light every time the reservoir got below half. If I filled the reservoir all the way, the fluid would splash out of the cap (poor seal). I cut the wire for the coolant level indicator as I got tired of looking at the light .

You might want to check the grounds next to your ECM. I stripped back a little wire and did an ohm test from the wire directly to my battery negative. The issue was the ground loops on the wire and corrosion. I replaced the ground loops and soldered them on there. This is the (eventual) ground for your fan relay, likely some of the instrumentation and likely many other important things.

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Thanks for the advice!

Now that I think about it, I did install new plugs and wires recently. I probably moved something around with my gorilla hands that caused this. My mechanic checked the fan relay, it was good. Wouldn't hurt to check those grounds though.

If I can't get the low washer light to turn off, I'll just cover it with some electrical tape.

The brand new coolant temp sensor in my 96 wouldn't turn the fan on until it was nearly overheating - it was a cheapo Napa part that many have had issue with here. OEM part fixed the problem. A quick way to check the fan was to turn on the AC - the fan should activate.
There could also be an issue in the two-wire harness to the sensor. I ordered that connector for my 98 when it began failing.
Also, if you just unplug the wiring harness from the washer bottle, the dash light should go out. Mine was finicky, the light would trip when it was about 80% full, so off it came.