Electrcal issues

mgmavant

mgmavant

Member
Hey folks, I have been having electrcal issues with my Jeep for a few months now, and I'm looking for some advice on what my next steps should be. My 08 JKU with 170k miles started having a no-start no electric power isse where I would go to start the Jeep and I would get a click and then loose all power to the Jeep (no dask lights, no dome light, no radio - nothing). I first checked and cleaned the leads on my battery, and that seemed to clear the issue for a little while. A couple months later, same issue that was resolved by cleaning and resetting battery leads and terminals - even though they were all tight and in great shape. Another month goes by, and same issue with single click, loose all electric power and can't start the jeep. This time, no matter what I do, I can't start the jeep, so I put a new starter on.

This seems to solve the problem for a short period of time (week or two), so when I have the issue again, I decide to check the starter to make sure it didn't crap out on me - starter was fine - so I decided to change out the battery and alternator (they were both working, but not very well and I knew I needed to replace them sooner rather than later).

Changed both of those out and added an additinal ground wire to make sure everything was grounded well (new wire from neg battery terminal to alternator mounting bracket). The Jeep ran great, until the same issue happened yesterday. Checked all the leads and terminals and everything looks great. Great voltage on the battery as well.

So current issue right now is that when I go to start the Jeep, I get a click in the TIPM box, and as soon as I try to start the Jeep, I loose all power to the Jeep. Easy to reset by just removing the positive terminal on battery and putting it back on and power is restored to the jeep. That seems to reset something. Power is good until I go to run the starter - thats when I get a click and then no power. If I reset the powr again, I can jump the jeep manually and it will run just fine (it's a 6spd manual).

Any thoughts on what i should do next?

Thanks for the help!

Spike
 
Wonder if something like the neutral safety switch is going bad. Tricking the jeep to think the clutch isn’t depressed and allowing you not to start.
 
I thought about that, but if it was just the switch, I wouldn't think I would loose all electric power after a single cycle of the ignition.

Is there an easy way to check the switch?
 
Try tightening the battery terminals before installing them. The factory terminals have a gap which you can see when looking at their bottom side. The gap widens over time, preventing the terminals from gripping the posts when you tighten them down. Take a pair of pliers and squeeze the terminals to close the gap before installing. Squeeze them a little at a time and test fit them. When installing the terminals, be sure to push them down all the way of the posts before tightening the nut. You should feel some resistance. Of course, clean the terminals and posts befpore final istallation.
 
mgmavant said:
Hey folks, I have been having electrcal issues with my Jeep for a few months now, and I'm looking for some advice on what my next steps should be. My 08 JKU with 170k miles started having a no-start no electric power isse where I would go to start the Jeep and I would get a click and then loose all power to the Jeep (no dask lights, no dome light, no radio - nothing). I first checked and cleaned the leads on my battery, and that seemed to clear the issue for a little while. A couple months later, same issue that was resolved by cleaning and resetting battery leads and terminals - even though they were all tight and in great shape. Another month goes by, and same issue with single click, loose all electric power and can't start the jeep. This time, no matter what I do, I can't start the jeep, so I put a new starter on.

This seems to solve the problem for a short period of time (week or two), so when I have the issue again, I decide to check the starter to make sure it didn't crap out on me - starter was fine - so I decided to change out the battery and alternator (they were both working, but not very well and I knew I needed to replace them sooner rather than later).

Changed both of those out and added an additinal ground wire to make sure everything was grounded well (new wire from neg battery terminal to alternator mounting bracket). The Jeep ran great, until the same issue happened yesterday. Checked all the leads and terminals and everything looks great. Great voltage on the battery as well.

So current issue right now is that when I go to start the Jeep, I get a click in the TIPM box, and as soon as I try to start the Jeep, I loose all power to the Jeep. Easy to reset by just removing the positive terminal on battery and putting it back on and power is restored to the jeep. That seems to reset something. Power is good until I go to run the starter - thats when I get a click and then no power. If I reset the powr again, I can jump the jeep manually and it will run just fine (it's a 6spd manual).

Any thoughts on what i should do next?

Thanks for the help!

Spike
Click to expand...
are there any accessories wired onto the battery post clamps?

Also check all the ground wire locations to make sure they are clean and tight:
1745197975554.png

these are under the heat shield near the cat on the passenger side
1745197994132.png

There is one on the passenger side, front near the headlight assembly

And the 2 on the body near the TIPM
 
Try having someone with a volt meter check the battery voltage while touching the posts only, while trying to crank it. If that checks fine, then put the leads on the cables only, while cranking.
 
So I checked all the grounds, and they were pretty good. Didn't get to the one behind the heat shield, but I ran two new ground wires - one from battery to alternator support structure (so basically engine) and then one from battery directly to chassis.

Voltages checked out fine before, and battery has plenty of amps. 12.6v without jeep running, about 14.2v with jeep running. Put battery on charger to make sure and it checked out fine (full charge). I didn't specifically check the voltage while starting - what's the expectation for that?

I ordered all new relays for the TIPM and will swap those out when they arrive (looks like a week for shipping). I didnt go for the OEM ones because they were like $27 a piece, so I went with some Standard Motor Parts relays from RockAuto. Had to order a new oil gasket for thr oil pan anyway, so I just added these guys to try out.

For accessories - i had a winch on that I somewhat recently took off. It was completely flooded (boys took the Jeep offroad and made a few stream crossings). I actually using the ground cable from that winch to ground battery to chassis. There's really no other electrical accessories.

At this point, if the relays don't work I'll probably move to the TIPM - unless there's some other ideas.

Spike
 
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