Electrical Trouble

904Jeep

New member
This issue came up a few says ago just before heading out on a trail ride. While waiting at idle my dashboard light flickered and then momentarily turned off and back on, doing the same with radio and AC fan, also causing the engine to drop RPM and run rough. this happened once until later on.

During the trail ride later the same day after going through several deep water crossings the issue repeated itself again, often several times in just a few minutes. This issue would continue regardless wether or not i was in deep water, out of water, idling, or moving. Although the issue was more frequent when in water or just after getting out of water.
In one instance my dash turned completely off bringing the radio and AC with it, only to not turn back on his time. I do not recall wether or not the engine turned off. This time after restarting the Jeep i was met with a check engine light, pulled a code P0750 (Shift Soleniod A Malfunction) out of the in dash code reader. I turned off the jeep and checked all fluids for water(none), and if the canbus/pcm was wet (it wasn't). Decided to continue on the trail ride. The issue continued to repeat itself but with less frequency, it would not occur again for the ride home.

After arriving home from the trail ride and restarting the jeep, i found the check engine light to have gone out, no codes pulled.

Several days went by without the issue occurring until today, the speedometer reset to 0 and back to actual speed while driving, the dash turned on and off while idling, and when sitting at a stop light, the dash, radio, AC, and even the engine completely turned off. Everything worked fine after restarting, no codes pulled, no check engine light.

The jeep is going in to the dealership on June 3rd but would like to hear your thoughts on what could be the issue, things to try, or anyone else that is having a similar problem. Afraid that the dealership won't fix under extended warranty due to modifications.
 

RUBINOT

Caught the Bug
I'm no expert by any means, but my first guess would a loose are faulty ground wire. Check battery for good clean connections.

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gtony12

Caught the Bug
also check the grounding straps from the body of your jeep to the frame. if this has come loose it would cause grounding issues.:thinking:
 

jeeeep

Hooked
This issue came up a few says ago just before heading out on a trail ride. While waiting at idle my dashboard light flickered and then momentarily turned off and back on, doing the same with radio and AC fan, also causing the engine to drop RPM and run rough. this happened once until later on.

During the trail ride later the same day after going through several deep water crossings the issue repeated itself again, often several times in just a few minutes. This issue would continue regardless wether or not i was in deep water, out of water, idling, or moving. Although the issue was more frequent when in water or just after getting out of water.
In one instance my dash turned completely off bringing the radio and AC with it, only to not turn back on his time. I do not recall wether or not the engine turned off. This time after restarting the Jeep i was met with a check engine light, pulled a code P0750 (Shift Soleniod A Malfunction) out of the in dash code reader. I turned off the jeep and checked all fluids for water(none), and if the canbus/pcm was wet (it wasn't). Decided to continue on the trail ride. The issue continued to repeat itself but with less frequency, it would not occur again for the ride home.

After arriving home from the trail ride and restarting the jeep, i found the check engine light to have gone out, no codes pulled.

Several days went by without the issue occurring until today, the speedometer reset to 0 and back to actual speed while driving, the dash turned on and off while idling, and when sitting at a stop light, the dash, radio, AC, and even the engine completely turned off. Everything worked fine after restarting, no codes pulled, no check engine light.

The jeep is going in to the dealership on June 3rd but would like to hear your thoughts on what could be the issue, things to try, or anyone else that is having a similar problem. Afraid that the dealership won't fix under extended warranty due to modifications.

did you do any deep water crossings before this most recent trail ride?
like others indicates, check your ground wires, battery ground - make sure everything is tight.
could also be a faulty cooling fan, does it spin up high when it's acting up?
 

FrankenJeeper

New member
I agree with above posts, check your battery cables and ground wires for good clean connection. Similar thing happened to me and turned out to be dirty battery posts not having a good clean connection.

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904Jeep

New member
Thank you for the replies.
Checked all known grounds and the alternator cable as well as some grounds on the battery terminal side were loose but still in contact.
Tightened them down and will see how things go the next few days.
Any idea if the P0750 Code was related to the grounds or if something is possibly wrong with the transmission?
 

gtony12

Caught the Bug
It could be from this issue. Also did you check your fluid levels transmission oil level I mean

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36Fan

New member
Possible water in one or more wiring harness connectors causing the CAN bus to cross signals, or wiring harness problem. With CAN bus systems, it could be anything when multiple items give problems at once.
 
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