2012 Tahoe 5.3 Shut down 3 months. Will not start. Help? Ideas? FIXED!

[TerryKing]

THANKS FLESS and WES! OK I will be on it again in the morning... I need to get the spare tire down and then move truck out and open my pit and move it back. THEN I can get at all that... Wow..

This'd Almost Be Fun in the Summertime.... Regards, Terry

 

[TerryKing]

FOUND Something: Going over the Fuel System Control Module tests in the link @Fless sent, before dropping the Spare Tire, AND:

SWAG: Check power on both sides of fuse #21 for the Fuel System Control Module.

So I tried to lift fuse #21 a little so I could probe it. Seems stuck. Use needle-nose pliers.. stuck. Rock it a little and it came apart!!!

I have the top half of the fuse and it looks corroded. The PINS are still in the electrical block. I will go out this morning and try to carefully pull those pins out. I have good Contact spray and will use that first.

Any pointers on handling this kind of broken fuse appreciated!!

@Fless THANKS for your Scientific Guess! It may have pointed to a/the problem.

Regards, Terry

 

[Fless]

Hopefully you can get those fuse legs out without damage. I don't have any good tips for that.

The regular fuses can be tested in-circuit using the test points that are on each fuse, but that won't necessarily test for damaged legs or full circuit continuity.



Hoping for an easy fix!

 

[TerryKing]

@Fless THANKS! I didn't ever notice those test points. Makes a lot of sense. Putting my head-mount magnifier on 82 year old eyes, I see those!

--- LEARNING ---
Regards Terry (Back after another priority job...)

 

[TerryKing]

@Fless THANKS! I didn't ever notice those test points. Makes a lot of sense. Putting my head-mount magnifier on 82 year old eyes, I see those!

--- LEARNING ---
Regards Terry (Back after another priority job...)

Wow do I HAVE to quote myself?? Sigh...

MAIN GOOD NEWS and a large WHAT TO DO???
Tried to extricate the broken fuse pins with several tools/probes etc. No luck. I was worried about breaking the pin stubs off altogether. So I 'connected' a clip lead between the two points.

Seat belt on, Key on.. FUEL PRESSURE right up to 45 PSI. Crank and immediate START/RUN! After 30 seconds the clip lead looked hot and I shut it down. The fuel pressure stayed high for a while after shut down and key removed.

WHAT TO DO??

- LONG TERM I don't feel I can trust the fuse socket . I need to find the two wires (One from Engine Control, one from Fuel System Control Module, right??) externally add a fuse holder and 25A fuse. Does anyone have access to the wiring diagrams and color codes??

- TEMPORARY: Maybe a Situation Horribleus I have used in a couple of corroded-contact emergencies in the past (Like my home power pole circuit breaker contacts with the electric meter bus. Don't Ask!). Vermont Winters are not friendly to contacts. SO:
- Inline "weatherproof" fuse holder with 3 inch leads of about #12 copper stranded wire.
- 25 Amp fuse to fit holder
- Two small ring-shank bronze nails with fuseholder wires wrapped and soldered to the top end of the nails.
- Carefully hammer the nails into the two original fuseholder sockets, same depth as a real fuse would go. At least it's not 120VAC
- Insert fuse.
- Cross fingers and other appropriate incantations. Key in, ON and START ! ? ! ?

Many THANKS to @Fless and @Wes and others fir helping me track this one down... !!

Couple photos follow. Any wire color code / info, pointers appreciated!



Regards, Terry

 

[iamdub]

Wow do I HAVE to quote myself?? Sigh...

MAIN GOOD NEWS and a large WHAT TO DO???
Tried to extricate the broken fuse pins with several tools/probes etc. No luck. I was worried about breaking the pin stubs off altogether. So I 'connected' a clip lead between the two points.

Seat belt on, Key on.. FUEL PRESSURE right up to 45 PSI. Crank and immediate START/RUN! After 30 seconds the clip lead looked hot and I shut it down. The fuel pressure stayed high for a while after shut down and key removed.

WHAT TO DO??

- LONG TERM I don't feel I can trust the fuse socket . I need to find the two wires (One from Engine Control, one from Fuel System Control Module, right??) externally add a fuse holder and 25A fuse. Does anyone have access to the wiring diagrams and color codes??

- TEMPORARY: Maybe a Situation Horribleus I have used in a couple of corroded-contact emergencies in the past (Like my home power pole circuit breaker contacts with the electric meter bus. Don't Ask!). Vermont Winters are not friendly to contacts. SO:
- Inline "weatherproof" fuse holder with 3 inch leads of about #12 copper stranded wire.
- 25 Amp fuse to fit holder
- Two small ring-shank bronze nails with fuseholder wires wrapped and soldered to the top end of the nails.
- Carefully hammer the nails into the two original fuseholder sockets, same depth as a real fuse would go. At least it's not 120VAC
- Insert fuse.
- Cross fingers and other appropriate incantations. Key in, ON and START ! ? ! ?

Many THANKS to @Fless and @Wes and others fir helping me track this one down... !!

Couple photos follow. Any wire color code / info, pointers appreciated!

View attachment 389180View attachment 389181

Regards, Terry

It looks like that fuse had a bad connection and, being a relatively high-amp circuit, the connection burned and corroded solid.

I believe that whole top panel that holds all the fuses is removable. You could find a good one from a part-out, in person or online, and swap it. Take a clear pic of it and compare it to one from another car.

I know @Doubeleive is familiar with this multi-layer assembly and might can offer more input.

 

[Doubeleive]

Wow do I HAVE to quote myself?? Sigh...

MAIN GOOD NEWS and a large WHAT TO DO???
Tried to extricate the broken fuse pins with several tools/probes etc. No luck. I was worried about breaking the pin stubs off altogether. So I 'connected' a clip lead between the two points.

Seat belt on, Key on.. FUEL PRESSURE right up to 45 PSI. Crank and immediate START/RUN! After 30 seconds the clip lead looked hot and I shut it down. The fuel pressure stayed high for a while after shut down and key removed.

WHAT TO DO??

- LONG TERM I don't feel I can trust the fuse socket . I need to find the two wires (One from Engine Control, one from Fuel System Control Module, right??) externally add a fuse holder and 25A fuse. Does anyone have access to the wiring diagrams and color codes??

- TEMPORARY: Maybe a Situation Horribleus I have used in a couple of corroded-contact emergencies in the past (Like my home power pole circuit breaker contacts with the electric meter bus. Don't Ask!). Vermont Winters are not friendly to contacts. SO:
- Inline "weatherproof" fuse holder with 3 inch leads of about #12 copper stranded wire.
- 25 Amp fuse to fit holder
- Two small ring-shank bronze nails with fuseholder wires wrapped and soldered to the top end of the nails.
- Carefully hammer the nails into the two original fuseholder sockets, same depth as a real fuse would go. At least it's not 120VAC
- Insert fuse.
- Cross fingers and other appropriate incantations. Key in, ON and START ! ? ! ?

Many THANKS to @Fless and @Wes and others fir helping me track this one down... !!

Couple photos follow. Any wire color code / info, pointers appreciated!

View attachment 389180View attachment 389181

Regards, Terry

I would try and find a local junkyard and grab the fuse box top and swap it out, when you pull it up there are sections under the bottom that are clipped in, a flat head screw driver will release the one you need, you might get lucky by pulling the box top out and be to get to it from under neath or patch a replacement fuse holder in. just lift those grey color handles and pull straight up. when you put it back or a replacement back in be sure it is on nice and snug so you don't have any other issues

 

[Doubeleive]

here is a listing for one online if you click thru the photo's you will see what it looks like underneath, on this one the sections on the bottom have been removed already

Fuse Box Panel Junction Relay Block 22798217 OEM GMC Chevy Cadillac 2010 - 2014✅ | eBay

Quality of product and service are our top priority. We aim to exceed expectations and every opportunity. When you are happy, we are too!.

www.ebay.com

 

[TerryKing]

WOW.. More Stuff I Never Knew!

@Doubeleive Do I understand this right??

So, the entire top panel section with all the relays and fuses PLUGS IN to a series of connectors that come from different sections of the engine and body??

So are the fuse sockets and relay sockets part of the removeable top?
IF I unclipped the top panel and the SECTION connector for that upper-right area, I could trace what wires went to that fuse??

Wow. So I am thinking that if I can do a 1/2Ass temporary connection, then in the Spring/Summer I can take this totally apart, get a used replacement top section (With an intact F21) reassemble it and have THAT fuse situation resolved.

I was already thinking that later I should remove, contact clean and replug ALL the Fuses and Relays.

Is There a decent aftermarket manual for these vehicles that would have most of this information?? I've done a lot of GM and Ford work but I'm about 20 years behind.

IT PLUGS IN. Blows my mind. All THOSE connectors should be cleaned next Spring. I Think. 200,000 plus miles on Vermont highways with salt air.. NOW I'm nervous... Should (semi-obviously) disconnect battery before removing that top panel??

Can't thank all you 'guys' enough! Regards, Terry

 

[Fless]

So, the entire top panel section with all the relays and fuses PLUGS IN to a series of connectors that come from different sections of the engine and body??

So are the fuse sockets and relay sockets part of the removeable top?
IF I unclipped the top panel and the SECTION connector for that upper-right area, I could trace what wires went to that fuse??

Yes to those three questions. Each harness block underneath will snap out of the upper part that holds the fuses and relays.

All good suggestions from the forum. You could look on Facebook Marketplace, Next Door, Craigslist, or a local junkyard, etc. for someone parting out a similar truck and see if they would sell the upper part of the underhood electrical center. Just be sure to inspect carefully, maybe pulling out all the fuses and relays and making sure the contacts are solid.

EDIT: you can also look at www.car-part.com, select your vehicle info, Zip code, item desired, and see yards that have your part, the price, and the distance from your Zip.