More electrical gremlins.

[mtudb24]

I'm at my wits end with this truck and its electrical issues. Replaced the IBS sensor in July, truck ran flawless from early July until this past weekend when the dash went haywire again and voltage on cluster would go from anywhere from 11.3 Volts at idle / startup to 15.8 Volts at 2000rpm which then set off all the ABS / Traction control lights on the dash again.

Yesterday, the remote start would work, 2 hours later it would not. Voltage at battery is 12.7V whether the battery cables are connected or not but when putting the truck into the first accessory position without it being started, voltage on the cluster shows 11.3 and sometimes 10.8Volts. Now the horn won't even even beep or sounds like like a kazoo when locking the doors with the keyfob. But 1 day later, its sounds at full power and truck runs great. I just don't get it anymore.

The truck has never struggled to start and the interior lights or LED bed lights are always 100% functional. The headlights are 100% solid as long as the truck isn't running. But once you start the truck, it all goes south.

My LED headlights would flicker on and off to nothing even though I had the tazer set to LED setting,

After the issues this past weekend, I decided to reset the whole jeep back to stock. Replaced all the LED lighting back to halogen and removed the tazer to see if that was the issue. Nope, even the factory halogen bulbs would almost dim to noting setting in the driveway at idle.

Gonna bite the bullet and install a new start stop battery put fuse 42 back in, and reconnect the negative aux battery cable to the negative post to get it all back to stock.

I can't believe that deleting the aux battery is actually my problem as so many JL and JT owners have done with no problems at all.

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[ShadowsPapa]

Yesterday, the remote start would work, 2 hours later it would not. Voltage at battery is 12.7V whether the battery cables are connected or not but when putting the truck into the first accessory position without it being started, voltage on the cluster shows 11.3 and sometimes 10.8Volts. Now the horn won't even even beep or sounds like like a kazoo when locking the doors with the keyfob. But 1 day later, its sounds at full power and truck runs great. I just don't get it anymore.

Has the PDC - fuse block - ever been off?
There's something messed up for you to read 12.7 at the battery terminals but the cluster show 2 volts less. It's got a power drop - voltage drop - somewhere telling it that the batteries are low when they aren't
I'm thinking a connection at the fuse block (PDC - power distribution center) or similar.

 

[mtudb24]

Has the PDC - fuse block - ever been off?
There's something messed up for you to read 12.7 at the battery terminals but the cluster show 2 volts less. It's got a power drop - voltage drop - somewhere telling it that the batteries are low when they aren't
I'm thinking a connection at the fuse block (PDC - power distribution center) or similar.

I'll look at that, but its never been off before.

Thanks

 

[mtudb24]

Has the PDC - fuse block - ever been off?
There's something messed up for you to read 12.7 at the battery terminals but the cluster show 2 volts less. It's got a power drop - voltage drop - somewhere telling it that the batteries are low when they aren't
I'm thinking a connection at the fuse block (PDC - power distribution center) or similar.

Well Papa, I went out to the truck today after work and the horn still wouldn't beep when locking the truck with the

key fob. I looked at the cluster, and the voltage was at 11.3V. It started fine and the voltage was all over the place at idle.

I shut it off and put a 1/2 turn on each of the 5 BEC / PDC bolts. After doing that, I also wiggled all 3 of the positive battery cables that are attached on the positive battery post. Nothing moved at first but when i applied a large amount of leverage and really twisted them, the cable closest to the firewall started to rotate ever so slightly (a few degrees of rotation at most). Now I've never removed any of the 3 ring terminals and only have only loosened the bolt at the battery post to change the battery when it went bad. I torqued that one down and then hit the lock button on the key fob and the horn was back beeping again. Remote start worked. Cluster with truck off, showed 12.5V. Cluster at idle never moved off of 14.3 and while driving it was between 13.8 and 14.3 the whole 30 minute ride. Headlights never flickered while at a stop light etc.

Was a BEC/PDC bolt not seated? Or was that ever so slightly loose ring terminal the issue? Possibly? I guess time will tell.

Thanks again for telling me to look at the PDC as I don't think I would have looked at that and checked the battery leads again.

 

[ShadowsPapa]

Well Papa, I went out to the truck today after work and the horn still wouldn't beep when locking the truck with the

key fob. I looked at the cluster, and the voltage was at 11.3V. It started fine and the voltage was all over the place at idle.

I shut it off and put a 1/2 turn on each of the 5 BEC / PDC bolts. After doing that, I also wiggled all 3 of the positive battery cables that are attached on the positive battery post. Nothing moved at first but when i applied a large amount of leverage and really twisted them, the cable closest to the firewall started to rotate ever so slightly (a few degrees of rotation at most). Now I've never removed any of the 3 ring terminals and only have only loosened the bolt at the battery post to change the battery when it went bad. I torqued that one down and then hit the lock button on the key fob and the horn was back beeping again. Remote start worked. Cluster with truck off, showed 12.5V. Cluster at idle never moved off of 14.3 and while driving it was between 13.8 and 14.3 the whole 30 minute ride. Headlights never flickered while at a stop light etc.

Was a BEC/PDC bolt not seated? Or was that ever so slightly loose ring terminal the issue? Possibly? I guess time will tell.

Thanks again for telling me to look at the PDC as I don't think I would have looked at that and checked the battery leads again.

I suspected a voltage drop somewhere - and now have to ask - the red terminal cover? That's been hot. do you know the story on that?

 

[mtudb24]

I suspected a voltage drop somewhere - and now have to ask - the red terminal cover? That's been hot. do you know the story on that?

I noticed that too when I popped it off. Wondering if that loose terminal (which is where the hot spot shows) got warm from the 15+ to 16 volts I've seen on the cluster? Nos sure what that cable supply's voltage too or where in the vehicle?

I don't think i have pulled that boot off since I changed the main battery 9 months ago.

 

[ShadowsPapa]

I noticed that too when I popped it off. Wondering if that loose terminal (which is where the hot spot shows) got warm from the 15+ to 16 volts I've seen on the cluster? Nos sure what that cable supply's voltage too or where in the vehicle?

I don't think i have pulled that boot off since I changed the main battery 9 months ago.

Yes, a loose connection pulling heavy amperage will get hot.
I think you've found it! (hope so, but looks positive)

 

[mtudb24]

Yes, a loose connection pulling heavy amperage will get hot.
I think you've found it! (hope so, but looks positive)

I hope so too. Today's drive and I just hit the remote start, and she beeped twice and fired right up.

Thanks again for pointing me to a voltage drop problem between the cluster voltage and the battery voltage not matching. Would not have looked their again at those connections with it being so intermittent. I was thinking it was something software related as the BCM controls the RVC other then the IBS sensor which had been replaced but still showed the same issues after replacing it.

 

[mtudb24]

I hope so too. Today's drive and I just hit the remote start, and she beeped twice and fired right up.

Thanks again for pointing me to a voltage drop problem between the cluster voltage and the battery voltage not matching. Would not have looked their again at those connections with it being so intermittent. I was thinking it was something software related as the BCM controls the RVC other then the IBS sensor which had been replaced but still showed the same issues after replacing it.

Solid voltage after setting for a few hours at the cluster which matches very closely to the battery readings.

Gonna run it for a while as is and if all goes well, re-install the tazer and my LED lighting, etc

 

[mtudb24]

3 days of flawless running and solid voltage with no fluctuations at idle or while driving. Knock on wood, its finally fixed and back to normal. Put all my LED's back in and put the tazer back to LED setting. Decided to give the engine bay a good cleaning for a reward

 

[mtudb24]

Funny story. After a month of running perfect, Thursday night the voltage went haywire again and all exterior lighting flickering, blower motor shutting off and windshield wipers barely sweeping (it was raining), and truck almost stalled when going into reverse backing up into the driveway.

Got home and sure enough that battery cable ring terminal was loose again on the post. WTH? There was at least 5 degrees of rotation of that ring terminal on the stud.

There has to be something on engine roll or some odd vibration that the nut keeps loosening up. So this time I put blue locktite on the stud and re-torqued the nut down it and its been solid since then.

HOWEVER, there is one caveat (nothing is ever straight forward right ). Since I pulled fuse 42 and disconnected the aux negative battery cable last fall, my stop start has never engaged. I have never ever once pushed the disable start stop button since I bought it new in 2020 and I know pulling fuse 42 only stops the engagement of the PCR relay and won't stop the ESS from working by using the main battery, but it has never gone into ESS in 11+months.

Now all of a sudden every stop light I hit, the ESS engages. If i push the ESS defeat button, it won't go into ESS mode.

Not that I care or am concerned about it, I just find it comical. i Guess I'll program the tazer to shut it off or push the button on the dash.

 

[ShadowsPapa]

Funny story. After a month of running perfect, Thursday night the voltage went haywire again and all exterior lighting flickering, blower motor shutting off and windshield wipers barely sweeping (it was raining), and truck almost stalled when going into reverse backing up into the driveway.

Got home and sure enough that battery cable ring terminal was loose again on the post. WTH? There was at least 5 degrees of rotation of that ring terminal on the stud.

There has to be something on engine roll or some odd vibration that the nut keeps loosening up. So this time I put blue locktite on the stud and re-torqued the nut down it and its been solid since then.

HOWEVER, there is one caveat (nothing is ever straight forward right ). Since I pulled fuse 42 and disconnected the aux negative battery cable last fall, my stop start has never engaged. I have never ever once pushed the disable start stop button since I bought it new in 2020 and I know pulling fuse 42 only stops the engagement of the PCR relay and won't stop the ESS from working by using the main battery, but it has never gone into ESS in 11+months.

Now all of a sudden every stop light I hit, the ESS engages. If i push the ESS defeat button, it won't go into ESS mode.

Not that I care or am concerned about it, I just find it comical. i Guess I'll program the tazer to shut it off or push the button on the dash.

Side effect of fixing a bad connection that it felt cause enough problem to disable the ESS.
Now that it's fixed........

I like the fact that ESS can point out other problems with the truck, electrical or otherwise.

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