Computer scan and check required

For strangeness like that you need an auto electrician. The scan tool computer can tell which controller is faulty.

https://www.google.com/search?q=auto+electrician+near+me

You have a unique issue and that is unusual.

https://www.google.com/search?q=2005+Jeep+Grand+Cherokee+Limited+5.7.+No+electrical+power+to+rear+of+vehicle

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have vehicle scanned for the trouble code --it will assist you in repairing problem

all cars are fixed by humans, computers only tools of the humans.
totally until SkyNet takes over, sadly.
no code posted, sad, no?
nor engines size
and is a engine question.

case in point a v6 has 2 banks and one or both banks can go lean.
we'd need all codes stored, no just one if more than one.
then we check to see if all cylinder are acting up or just 1.
or one bank,
see? its called diagnosis, we use tools meters , gauges and scan tools to do all that.

Check the fuel filter,nozzles and clean the injector mouth

The check engine light is a general warning that you have a problem that needs attention. Diagnosis of the problem requires a computer scan. You can have this done at most auto shops and parts stores, and many will run the scan at no cost to you. Your transmission problem may be the cause of the light, but even if it's not, the scan may give you some insight into it as well.

Bill B

You need to check ...was the computer swapped from one to the other?
Was there any componenet changes on the engine such as old one had a/c this one don't?Is the TPS(throttle positioning switch) plugged in...all the fuses checked ok...look under the hood at the fuse tray and test them all with a test lite, something obviously computerized is not reading info to the ECM(computer).
Scan for codes once you get the idle down.The engine light must be lit?? Put your scanner in and see what you have onboard for codes.
Good luck!!

it mean that a wheel sensor is not working properly
your car computer cannot get a proper wheel reading
you need to scan the code at your local garage that are equiped with a scan tool

It depends on which light you are referring to. If it was the oil pressure light and the oil level was low, then adding the oil to the right level should have made the light go out unless there is another issue. If the light you refer to is the check engine light, however, then I would suggest taking the vehicle to an autoparts store and have them scan the computer for any fault codes stored. The check engine light is to alert you that the computer has noted a fault in one of the car's systems and getting the codes will show what the computer has identified so corrective action can be taken. Hope this helped and best wishes.

I would be thinking that there is a good chance that you need to be checking out replacing the computer, if you aren't getting any communication with the proper scan tool then the computer isn't communicating with anything in the vehicle...... I would have guessed first off that the ignition control module might be bad but that is obviously part of the computer also, I would be looking in that direction.

- air filter replace
- check spark plugs
- check PCM via diagnostic @ garage
- Tire check: Pressure & Type ok
- check wheel alignment
- check for bad transmission joints
- check oil in gearbox and transmission case

pls. keep me updated, thanks