Fan runs continuously

[mrblaine]

Thanks. Yeah, the check engine light and check gauges lights are both stuck on. They clear them and they both immediately come back on. The mechanics here in ethiopia can't figure it out. They don't know what to do. They don't know this kind of vehicle and are extremely limited. Any parts I have to ship into the country as well. Tough situation only made worse by my own ignorance.

When you say they clear them, are they doing that with a scanner and if so, what codes are showing?
When the engine is running and the check gauges light is on, one of the gauges will be way off for that to happen. We are speculating that it "should" be the temp gauge which is defaulting to full hot to warn of a bad sender. If it defaulted the other way that would me the check gauges light comes on all the time right after the engine is started. But, we aren't sure so which gauge is showing a way too high or way too low reading.
Typically a very low voltage will trip the check gauges light.
Too low oil pressure
Too hot on the temp gauge

Which one is out of range?

 

[Jeep in Ethiopia]

I had my helper peruse the diagram. He reports that if the dash gauge is working, the temp sender should also be working. If the relays fail closed, the fan will run with the key off. The power to the relays is direct from the battery with a circuit breaker on the ground side.

A bad sender would make the fans run full time and a check gauges light turn on due to the gauge being pegged one side or the other.

If the dash gauge is working, then the sender is likely good and the issue is between the sender output, PCM and its output to the relays.

If one unplugs the connector off of the sender, that should force the fans on full time with the key on as a default to prevent overheating in the event of a sender failure.

About the most we can decipher from the wiring diagram.

Interesting.

1. The temp gauges work on the dash as far as I can tell--reads normal temps like usual.
2. When the keys are removed, the fan stops
3. I've replaced the relays and the results are the same--the fan runs continuously once the jeep is started.
4. So, if unplugging the connector to the sensor (sender?) will only result in the fan continuing to run, then that won't help me decipher anything it seems.

Sooooooo, we're down to it definitely being the PCM?

 

[AMS417]

Not saying anything for certain, not over the internet without even having hands on it. I would replace the sender first, just because its cheap and we haven't ruled it out 100%. It could be defaulting to fans on because the sender is bad. I would check the wires carefully for damage back to the PCM. Unplug and clean the PCM connections, disconnect the battery again to reset the system. If all that fails to resolve the issue, either search for someone with electrical diagnostic skill to check it over, or roll the dice on a PCM.

 

[Jeep in Ethiopia]

Not saying anything for certain, not over the internet without even having hands on it. I would replace the sender first, just because its cheap and we haven't ruled it out 100%. It could be defaulting to fans on because the sender is bad. I would check the wires carefully for damage back to the PCM. Unplug and clean the PCM connections, disconnect the battery again to reset the system. If all that fails to resolve the issue, either search for someone with electrical diagnostic skill to check it over, or roll the dice on a PCM.

When you say "sender" you mean the temperature sensor, right? Just to be clear.

 

[AMS417]

When you say "sender" you mean the temperature sensor, right? Just to be clear.

Sender, sensor, switch. The thing I pointed to in the picture earlier. That thing.

 

[Jeep in Ethiopia]

Sender, sensor, switch. The thing I pointed to in the picture earlier. That thing.

Thank you. I'll update in this forum once I've had a chance to check this.

 

[mrblaine]

Thank you. I'll update in this forum once I've had a chance to check this.

Find the key on off method for pulling the codes or get them from the scanner the guys are using to turn off the CEL and post those up. That will get us closer than where we are now.

 

[CharlesHS]

A good source of parts for the TJ would be Rock Auto online.

Coolant Temperature Sensor

 

[mrblaine]

A good source of parts for the TJ would be Rock Auto online.

Coolant Temperature Sensor

Given my recent experiences with Rock Auto, I'm not sure they even know where Ethiopia is.

 

[B00mb00m]

Given my recent experiences with Rock Auto, I'm not sure they even know where Ethiopia is.

Their packaging on oil pans does leave something to be desired.

 

[mrblaine]

Their packaging on oil pans does leave something to be desired.

I've ordered batches of 20 unitbearings from them at least 8 times previous. Shows up in 1-2 boxes, takes 2 days to get here and cost me 25-30 bucks in shipping.
Last order for 20 shows up in the following manner and takes about 8 days all in for a cost of 125.

 

[B00mb00m]

I've ordered batches of 20 unitbearings from them at least 8 times previous. Shows up in 1-2 boxes, takes 2 days to get here and cost me 25-30 bucks in shipping.
Last order for 20 shows up in the following manner and takes about 8 days all in for a cost of 125.
View attachment 170895

$125 shipping!?!?!

 

[Jeep in Ethiopia]

Find the key on off method for pulling the codes or get them from the scanner the guys are using to turn off the CEL and post those up. That will get us closer than where we are now.

thanks, I've reached out to them for the codes. They may not have kept them in their records.

 

[Jeep in Ethiopia]

I've ordered batches of 20 unitbearings from them at least 8 times previous. Shows up in 1-2 boxes, takes 2 days to get here and cost me 25-30 bucks in shipping.
Last order for 20 shows up in the following manner and takes about 8 days all in for a cost of 125.
View attachment 170895

Shipping here is a joke. No addresses here. Have to use Embassy pouches. Real hassle. I'll have to fly home in December and get the parts and bring them back. I can have colleagues bring them into the country if they are flying back and forth. Dubai is another option, potential, but I'm not so keen. From there, things get stuck in customs.

 

[Steel City 06]

thanks, I've reached out to them for the codes. They may not have kept them in their records.

You can get the codes by putting the key in the ignition and cycling it from Accessory to Run 3 times (without starting it). The codes will flash across the odometer followed by "donE".

 

[Jeep in Ethiopia]

Sender, sensor, switch. The thing I pointed to in the picture earlier. That thing.

ok, so I pulled it, after disconnecting the battery, and started it up. No change. Fan runs continuously. And what, again, does this show?

I forgot to check the temp gauge on the dash when I did this to see if the engine temp was going up at all.

I'll be out until Monday to check anything again.

See attached video file.

https://drive.google.com/file/d/18e6ljEAPNRbnAmAlCFyOMxTvfhNrjXA0/view?usp=sharing

 

[mrblaine]

You can get the codes by putting the key in the ignition and cycling it from Accessory to Run 3 times (without starting it). The codes will flash across the odometer followed by "donE".

It doesn't have to go all the way back to ACC.

 

[Steel City 06]

It doesn't have to go all the way back to ACC.

Whichever position is forward of the release position. Not sure of its actual name

 

[mrblaine]

Whichever position is forward of the release position. Not sure of its actual name

ACC used to be 1 click back past the point where the key can be removed. I'll have to check again.

 

[Jeep in Ethiopia]

Ok, so I had a minute to stop by my jeep today and get the codes. I didn't stay for the duration of codes that were continuously spitting out.

Attached are some of them along the way (not sure if the P followed by numbers is an error code).

Or maybe I'm confused and the codes run for a while until eventually it shows just one code? And I should have waited to the end of this list of codes? Again, I didn't stay there to the end as I had to leave right away. I can check more thoroughly tomorrow.

I did return to the car a bit later and attempted it again. However, no codes were showing at all the second time. The check engine light only flashed for a short period. But no codes to be shown.

Alrighty, now what.