No start signal on 07 JKU

WSS

WSS

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Another no crank, no start thread. I have 12.5v at battery, cleaned the ground and pos terminal on battery, cleaned and reattached grounds around and in engine compartment.

One clue is m27 fuse (ign sw win mod) was blown. I replaced and a few items are working again, but still no crank.

I tested pin 86 on K3 no 12v when turned to start. Also no signal on pin 87 or at the starter solenoid start wire.

This is sudden and no trick has been successfully applied.

JScan reads this:

IMG_9580.jpeg
 
WSS said:
I will check. The dash was swapped with something from an SRT.
Click to expand...

You can pull up on the yellow fuse in the engine compartment I think it's called a IAD or something like that, it will disable the security system.
 
BLACKJKU said:
You can pull up on the yellow fuse in the engine compartment I think it's called a IAD or something like that, it will disable the security system.
Click to expand...

Ok, I pulled it yesterday and checked it for continuity, then duly put it back in.

Meanwhile, I have pulled the ignition switch and found a little broken pin loose in the switch. i presume it is important and part of the ignition key part. Does this sound right?
IMG_9588.JPG



IMG_9587.JPG
 
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UPDATE! FIXED.

The broken pin is a door chime actuator. I installed the new ignition switch without the broken pin. Everything works except the annoyong door chime. Starts, gauges work, dash panel stuff is operational.

I used chat gpt alot for this project and it steered me wrong most of the time. However, it did give ideas. Chat gpt uses internet solutions, we know how many of those are not correct. It also had a hard time between tj and jk. It still has a lot of learning to go.
 
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Well, I was over zealous. The no start issue reared it's head again. This time on a trail. We went to Calico (ghost town here in so cal) to do Doran and Odessa. The plan was to BBQ at the top of Doran at the Bismark mine and do Odessa back down. About 3/4 way up Doran, It would not start. Scary feeling. Eventually it did start and we skipped Odessa and opted for the easy Phillips route back to civilization. We chose Monday to avoid the crowds and we did. We did not see a single vehicle on the trail. Now, we did have a Garmin inReach and my starlink was hitting some impressive speeds, so we had communication.

Here is a video of what the Doran double falls looked like yesterday:



Some revisited facts, I pressure washed the engine compartment before the issue started. I changed the ignition switch (which seemed to cure the problem), I have blown M27 (10 amp) twice now when the problem occurs. It is not every time it blows. I also replaced my leaking locker air comp before this issue arised. The locker air comp stops working when the M27 fuse blows. No red light on dash. It is intermittent.

Any thoughts or advice is appreciated.
 
As an update, I found two issues on the m27 circuit. One was the new compressor has a cheap 12 connector. I fixed it and the variable noise and speed went away. When wiggling the harness, the motor would vary its speed. The second was someone “spliced” into the ignition “on” wire that connects the m27 fuse. A, it had too many things on it and B, the splice was stripped wires wrapped and taped, no scotch locks, t taps, etc. when I cut into the splice/removed tape, the ignition worked and sent a signal to start and it started. So, I bought some T Taps from McFadden Dale hardware and just need time to tidy up the loose ends. I did move the compressor hot lead to another switched circuit, the one that is in line with the switched cigarette plug. Fingers crossed that I’ve found it.

I also bought a Dorman clock spring today. I’ve got all my tools out in the right area. I’m going to attack that while I’m there.
 
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Well, the issue is back. Frustrating. I have the TIPM out and have cleaned it good and used contact cleaner on the harness plug in side. I'll put it back in today. I will also look at the neutral safety switch (it has a trans out of a 2009 Dodge ram.

The issue (at the moment) seems to arise when the Jeep is warm or been driven and up to temps. There is no 12v to the starter solenoid when key is turned to start. Something is blocking the signal, short, bad NS switch, etc. Starter spins the motor easily when jumped at the starter. On pre OBDI vehicles, turn the key to run and jump the starter and you are at least running.

Is there any module or section on a Jscan that will spot a faulty neutral safety switch?
 
WSS said:
Well, I was over zealous. The no start issue reared it's head again. This time on a trail. We went to Calico (ghost town here in so cal) to do Doran and Odessa. The plan was to BBQ at the top of Doran at the Bismark mine and do Odessa back down. About 3/4 way up Doran, It would not start. Scary feeling. Eventually it did start and we skipped Odessa and opted for the easy Phillips route back to civilization. We chose Monday to avoid the crowds and we did. We did not see a single vehicle on the trail. Now, we did have a Garmin inReach and my starlink was hitting some impressive speeds, so we had communication.

Here is a video of what the Doran double falls looked like yesterday:



Some revisited facts, I pressure washed the engine compartment before the issue started. I changed the ignition switch (which seemed to cure the problem), I have blown M27 (10 amp) twice now when the problem occurs. It is not every time it blows. I also replaced my leaking locker air comp before this issue arised. The locker air comp stops working when the M27 fuse blows. No red light on dash. It is intermittent.

Any thoughts or advice is appreciated.
Click to expand...

Mmmmm pressure washed engine . Was watching a video on uTube . “ I Do Cars “ He def knows his stuff .
He had mentioned that washing under the hood can cause corrosion on the pins at electrical connection points .
It doesn’t happen right away .
Can take a couple weeks or longer B4 electrical gremlins appear .
Safer solution is a damp rag . Won’t get into the tight spots but also less chances of messing something up .
 
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Speartip said:
Mmmmm pressure washed engine . Was watching a video on uTube . “ I Do Cars “ He def knows his stuff .
He had mentioned that washing under the hood can cause corrosion on the pins at electrical connection points .
It doesn’t happen right away .
Can take a couple weeks or longer B4 electrical gremlins appear .
Safer solution is a damp rag . Won’t get into the tight spots but also less chances of messing something up .
Click to expand...

Pressure washing is risky. I have had bad luck in the past washing chevys. This would have been a very quick reaction. I have not seen any corrosion or electrolysis on any of the parts or connectors. The TIPM looks fine, nothing but dust. My guess was moisture from pressure washing the area around the TIPM but I have not seen any "smoking gun" yet.
 
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WSS said:
Well, the issue is back. Frustrating. I have the TIPM out and have cleaned it good and used contact cleaner on the harness plug in side. I'll put it back in today. I will also look at the neutral safety switch (it has a trans out of a 2009 Dodge ram.

The issue (at the moment) seems to arise when the Jeep is warm or been driven and up to temps. There is no 12v to the starter solenoid when key is turned to start. Something is blocking the signal, short, bad NS switch, etc. Starter spins the motor easily when jumped at the starter. On pre OBDI vehicles, turn the key to run and jump the starter and you are at least running.

Is there any module or section on a Jscan that will spot a faulty neutral safety switch?
Click to expand...

Some years of the JK's the neutral safety switch is located inside of the trans, when the trans gets hot sometimes the switches would fail. Just maybe the problem is on more then just the JK's.
 
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BLACKJKU said:
Some years of the JK's the neutral safety switch is located inside of the trans, when the trans gets hot sometimes the switches would fail. Just maybe the problem is on more then just the JK's.
Click to expand...

The trans in my JKU is a 545rfe (most likely🤷‍♂️) I think the sensor is outside. BUT, I did some testing and found/traced the problem to the tipm. I can jump pin 30 to 86 on k3 in the tipm and the starter cranks over the engine. The tipm did not send a signal out of 87 to 86. I purchased a tipm from mak’s and hope to have it to me soon.

Anyone have insight on the tests I did showing the tipm is the problem? It is the original with a date code of 2007
IMG_9679.jpeg


IMG_9682.jpeg
 
WSS said:
The trans in my JKU is a 545rfe (most likely🤷‍♂️) I think the sensor is outside. BUT, I did some testing and found/traced the problem to the tipm. I can jump pin 30 to 86 on k3 in the tipm and the starter cranks over the engine. The tipm did not send a signal out of 87 to 86. I purchased a tipm from mak’s and hope to have it to me soon.

Anyone have insight on the tests I did showing the tipm is the problem? It is the original with a date code of 2007
View attachment 129183

View attachment 129184
Click to expand...

The auto trans used in 2007-2011 wranglers is the 42RLE .

The 545RFE were available in sone Chrysler products but not the Wrangler
 
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