I am $12000 into this and my wife is gonna lost it.

[SouthernBornRebel]

You may be able to get OBDll MX+ and AlfaOBD, IF you could get a copy of someone's backup file before they messed with theirs, you could load the BCM and all back to factory, which may solve your issues.

 

[BobsToyShopinSC]

I have had some strange things like this happen in the past and almost every one of them has been connector issues. For a 2007 Chevrolet truck 4 or 5 codes seemingly unrelated appeared at once. I removed every connector from the computer and sprayed the heck out of them with electronics cleaner (both male and female side and then put then on and off multiple time spraying between. That fixed it and I had no more issues. Also had a 1996 Buick throw codes saying the ABS control unit was bad ($600 with me doing the work). Removed all connectors from ABS unit and did the same process. Issues were fixed with no new parts. About any dealer or mechanic would have replace expensive parts in both cases because that is what the code indicated. So that is my first method for attacking any strange electronics or code issue. I did have an issue with 2008 Cadillac DTS where internal connectors inside a 2 part fuse box were fried and I replaced the box for expediency. If it happens again I will take the time to disassemble the bad connectors and put them outside the fuse box or just replace the connector.
Sadly many good parts are discarded because codes don't show connector issues which cleaning will often solve as has been mentioned by others. My method may not solve it but is my first thing to try. Have not yet had an issue with major through firewall connectors but would be my first thing to try there as well. Be careful with fuse boxes though as some come apart easy but don't go back together easily.

 

[Annoyedramowner]

I apologize for the long wait. I have been working nonstop and haven’t had time. Finally got around to messing with the truck again. I did too many things to tell y’all what was wrong with it starting wise. It starts. I took apart all grounds, cleaned, and put back on. Took connector cleaner to the win module and a couple other major connectors. It decided to start. Finally. But new/different issue now. Attached are the codes it reads. The airbag one has existed since I bought the Truck off my father in law he damaged the connector under the drivers seat. They wanted too much money to fix it.

 

[04fxdwgi]

How old is the battery?
With all those comms errors and low voltages, I would be looking at the battery, fuse panel or some problem on the main power circuitry and ALL grounds.

 

[Annoyedramowner]

I would have to check again, but I don’t remember it being more than a year and a half old. I also put the battery on a battery tender for the last week that I have not worked on it. It was last night reading 12.3 V.

 

[Daw14]

Battery at resting voltage should be no less than 12.6 volts.
A toaster type tester puts a load on it , for the test .

 

[David H]

reading 12.3 V.

12.3 at rest is not very good. A load test will tell the story.

That's a lot of codes. Just a thought, last month my cruise control stopped working. I pushed the fuse down completely and that was it. All other fuses were the same. They all got pushed down 1/8 inch or so. This has been mentioned on this forum a number of times.
Good luck.

 

[Wild one]

I would have to check again, but I don’t remember it being more than a year and a half old. I also put the battery on a battery tender for the last week that I have not worked on it. It was last night reading 12.3 V.

Get yourself one of these battery testers. At 12.3v your battery isn't in great shape and probably should be replaced.

100 Amp, 6/12V Battery Load Tester

Amazing deals on this 100 Amp 6/12V Battery Load Tester at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

 

[TJP440]

March 2026
Bought a Powertrain product remanned engine to replace the engine ( this isn’t my first time replacing an engine) made sure to replace most of the basic pulleys and all spark plugs. The coils were recently replaced in the last couple years. Replaced it started the truck at least 20 times. Had an exhaust leak. My wife didn’t tighten her side well enough when putting it back together. We fixed it and couldn’t make it start after that. After speaking with my local shop they said to try multiple keys. I only had one. It was then said to replace RF module. We did today. It still doesn’t start. The dash back light turns on but nothing else. No clicking when you turn the key. Tried starting it at the starter with a screw driver. It didn’t try to turn over but you could hear the starter engage to try. I don’t hear the fuel pump engage when you turn the key either. The fan doesn’t blow. We have checked all connections to make sure they are tight and together as well as all relays, fuses, and battery terminals.

EDIT: Didn't note the previous post on load testing the battery

While not being overly familiar with electrical portion of these trucks basic electrical diagnosis should still apply. A couple of things stand out to me.
1.Replaced it started the truck at least 20 times.
2. Had an exhaust leak.
3. We fixed it and couldn’t make it start after that.
4. The dash back light turns on but nothing else.
5.No clicking when you turn the key.
6.Tried starting it at the starter with a screw driver. It didn’t try to turn over but you could hear the starter engage to try.
7. I don’t hear the fuel pump engage when you turn the key either.
8. The fan doesn’t blow.
Looking at the above list the first question is, Have you checked the battery Voltage at terminals while trying to start it?
I have had what appeared to be a perfectly good battery DIE within a minute of shutting a vehicle off. It would activate the gauges but do nothing when trying to start it. A minute earlier all was fine (running off the alternator). Checked the battery with voltmeter and 12.5V so I ASSumed it was good
After 3 days of chasing my tail, I happened to have the Voltmeter in a visible location reading 12.4 with the key in the ON position.
As soon as I turned it to start the VM dropped like a rock to 1V or less.
Watching it, it would slowly climb back up to 12.5 V.
I have been working on cars for well over 50 years an have NEVER encountered the above. I also spent 25+ years in engineering so I should have know better.
I have read of others having similar experiences with todays "QUALITY" batteries. They will show voltage but have very limited current capacity. purportedly this is due to bean counters reducing the amount of lead connecting the plates.

The fact that "The dash back light turns on but nothing else" is what made me think of this as the dash back light draws very little current. Had I done a load test on the battery the problem would have been immediately apparent. Damndest thing is I had a Load tester on the shelf about 10 feet away

I have been working on cars for well over 50 years an have NEVER encountered the above. I also spent 25+ years in engineering so i should have know better.
If the battery checks OK, I would start following the main feeds off the battery to the PCM and other distribution "arteries". Do check the in and OUT Voltages as well at relays, fuses etc.
If you are comfortable enough with electrical things you can also JUMPER across the relays to see if a non-working items (Fuel pump, fan, starter etc.) turn on.
If so then you either have a bad relay or it's not getting it's signal from the source.
I, as others are a bit baffled by your ongoing problems. Item 3 on your list is of concern as most times the last thing done causes the subsequent problem, but with your previous issues that may not be the case.
Might also get access to shop manual if they have flow charts in them. They can be VERY helpful
Do Keep us posted

 

[Yardbird]

I had a car that would start some times and not others. It went on for a while until one night it would just click. Not even jumping would start it.

My drunk friend grabbed the jumper cable just as I hit the starter, causing a spark, and blowing half the top off the battery.

Upon inspection, the post was making minimal contact inside the battery. It was seemingly broken and making pressure contact until a load was put on the battery.

It had been doing this for a week or so before the incident. I thought it was bad cables, not inside the battery.

New battery fixed everything, thanks to my drunk friend.

 

[EdGs]

I had a car that would start some times and not others. It went on for a while until one night it would just click. Not even jumping would start it.

My drunk friend grabbed the jumper cable just as I hit the starter, causing a spark, and blowing half the top off the battery.

Upon inspection, the post was making minimal contact inside the battery. It was seemingly broken and making pressure contact until a load was put on the battery.

It had been doing this for a week or so before the incident. I thought it was bad cables, not inside the battery.

New battery fixed everything, thanks to my drunk friend.

Damn, what a way to find that.

 

[TJP440]

EDIT: Didn't note the previous post on load testing the battery

While not being overly familiar with electrical portion of these trucks basic electrical diagnosis should still apply. A couple of things stand out to me.
1.Replaced it started the truck at least 20 times.
2. Had an exhaust leak.
3. We fixed it and couldn’t make it start after that.
4. The dash back light turns on but nothing else.
5.No clicking when you turn the key.
6.Tried starting it at the starter with a screw driver. It didn’t try to turn over but you could hear the starter engage to try.
7. I don’t hear the fuel pump engage when you turn the key either.
8. The fan doesn’t blow.
Looking at the above list the first question is, Have you checked the battery Voltage at terminals while trying to start it?
I have had what appeared to be a perfectly good battery DIE within a minute of shutting a vehicle off. It would activate the gauges but do nothing when trying to start it. A minute earlier all was fine (running off the alternator). Checked the battery with voltmeter and 12.5V so I ASSumed it was good
After 3 days of chasing my tail, I happened to have the Voltmeter in a visible location reading 12.4 with the key in the ON position.
As soon as I turned it to start the VM dropped like a rock to 1V or less.
Watching it, it would slowly climb back up to 12.5 V.
I have been working on cars for well over 50 years an have NEVER encountered the above. I also spent 25+ years in engineering so I should have know better.
I have read of others having similar experiences with todays "QUALITY" batteries. They will show voltage but have very limited current capacity. purportedly this is due to bean counters reducing the amount of lead connecting the plates.

The fact that "The dash back light turns on but nothing else" is what made me think of this as the dash back light draws very little current. Had I done a load test on the battery the problem would have been immediately apparent. Damndest thing is I had a Load tester on the shelf about 10 feet away

I have been working on cars for well over 50 years an have NEVER encountered the above. I also spent 25+ years in engineering so i should have know better.
If the battery checks OK, I would start following the main feeds off the battery to the PCM and other distribution "arteries". Do check the in and OUT Voltages as well at relays, fuses etc.
If you are comfortable enough with electrical things you can also JUMPER across the relays to see if a non-working items (Fuel pump, fan, starter etc.) turn on.
If so then you either have a bad relay or it's not getting it's signal from the source.
I, as others are a bit baffled by your ongoing problems. Item 3 on your list is of concern as most times the last thing done causes the subsequent problem, but with your previous issues that may not be the case.
Might also get access to shop manual if they have flow charts in them. They can be VERY helpful
Do Keep us posted

Do be aware a bad cable can act the same. he stated jumpering the statrter solenoid seemed to engage the solenoid but it may not have had enough current to turn the motor. On a newer vehilce, Not sure what else might be involved to get it to turn over.

 

[Annoyedramowner]

I have an appointment with my local shop this week. Here’s my last ditch thoughts for this truck before paying them a ridiculous amount of money. I’m trying to see if it’s possible the alternator could be bad. I’ll have to do some more voltage testing for the battery and see about it as well. With so many low voltage codes I figure it has to do something with either of those.

 

[RamDiver]

I have an appointment with my local shop this week. Here’s my last ditch thoughts for this truck before paying them a ridiculous amount of money. I’m trying to see if it’s possible the alternator could be bad. I’ll have to do some more voltage testing for the battery and see about it as well. With so many low voltage codes I figure it has to do something with either of those.

Did you ever load test the battery with a toaster-style battery load tester?

This is one of the least expensive and easiest tests to perform.

A failing battery is likely one of the most common points of failure for our rolling microcomputers.

.

 

[ookab]

Thanks for the details.

Your descriptions add a myriad of potential possibilities, but a much more defined direction than previously stated.

The first thing that stands out is that an intermittent starting problem appears to have begun in the summer of 2024.

With the age of the truck, faulty grounds, chaffed wiring and corroded connectors should be considered, especially after an engine replacement.
Add to that, displaced connector pins during reassembly.

I'm trusting that before the summer of 2024, there was no starting issue, and therefore, this may have been the beginning of the same problem that you're now experiencing.
Just a possibility, because intermittent faults can be very confusing and difficult to isolate.

As Burla suggested, the WIN module could potentially cause these problems, and it is worth the time to verify proper functionality. WIN faults are notorious for creating intermittent grief.
You will find many threads discussing troubleshooting WIN module faults.

Also, search YouTube for troubleshooting, repair, and replacement of WIN modules.




From the information above, I would start my search here. Review anything and everything within reach of this work area, and any other activities performed during this rework session.
It sounds like something changed from the start to the finish of this rework.

Also, were all the common grounds completely refurbished and cleaned to bare metal during the engine replacement activity?

Our rolling microcomputers are extremely sensitive to anything but near-perfect B+ and ground connections.

.

Had many similar issues but before throwing parts at it I check battery, fuses, scanned, and then got an ECT300 found that I simply had corroded connections on starter and one ground was all it was!!! Spent a month solid recovering from surgery and studying the ends and outs of this subject and basic diagnostic tools from harbor freight and following proven trace methods quickly solved it all and leaves me baffled as to why it cant be more simple to do DIY work on modern vehicles? Would be really nice to have mitchell or a similar program included with purchase for financing duration at the very least. Just my thoughts and one of my first comments.