No start 95 S

[Husker6.5]

Behind the glove box near the ECM on the firewall above the heater box.

DTC codes 51 and/or 57.

 

[jrsavoie]

Did you add any extra grounds? It seems I remember you saying you added the extra ground to the passenger battery box. Not sure about anything else.

I know you should not have to add grounds - other than the ground by the heater blower. That is a know trouble point

I always add a ground wire from the battery to the stud at the back of the engine. I have seen that stud lose continuity several times.

 

[packratt]

Behind the glove box near the ECM on the firewall above the heater box.

DTC codes 51 and/or 57.

What component does the wire going to that ground go to? I pulled the PCM box out and can't find it. Looking through the glove box the heater box goes up to the top of the dash and over to the passenger side wall.

Unfortunately I probably did have a 57 in the first mass of codes where I thought I got off count in the 50s. It never reappeared after I cleared them the first time.

 

[jrsavoie]

I'd start by pulling the intake and looking for "chafed" spot on the loom

I have snuck an engine harness out without pulling the lower intake before. I do not remember if I had to pull it later to get everything hooked back up.

But since I was shit canning the harness and replacing it with a new harness I wasn't to gentle in yanking it out.

Did you double check your grounds? Seems I had at least a couple of vehicles that had all but one tiny ground on the back stud. The other tiny ground was on a different stud very close.

Good or bad, I always moved that ground over with the rest.

 

[packratt]

Did you add any extra grounds? It seems I remember you saying you added the extra ground to the passenger battery box. Not sure about anything else.

I know you should not have to add grounds - other than the ground by the heater blower. That is a know trouble point

I always add a ground wire from the battery to the stud at the back of the engine. I have seen that stud lose continuity several times.

Haven't added any grounds other than a battery to fender that was missing.

I don't like the looks of the braided firewall to frame and block to firewall. Will replace them and add one from battery to rear stud.

 

[jrsavoie]

What component does the wire going to that ground go to? I pulled the PCM box out and can't find it. Looking through the glove box the heater box goes up to the top of the dash and over to the passenger side wall.

Unfortunately I probably did have a 57 in the first mass of codes where I thought I got off count in the 50s. It never reappeared after I cleared them the first time.

I was under the impression that, that ground went to the ECM and tied into the heater blower ground. On the older vehicles the heater blower ground frequently suffered from melt down at the connection right by the ECM and the blower resistor.

I was told that if you had overheating at that connection it was a possible sign that the heater blower was on it's way out and using to many amps to run.

 

[jrsavoie]

If you pull the lower intake remember 4 of the bolts take sealant on re-install - I think the stud with all the grounds going to it is one of the intake bolts that takes sealant

 

[jrsavoie]

If you have to pull the S intake, I would try to find an F intake to re-install. I would not install an S intake unless I was in a bind for time

 

[packratt]

I was under the impression that, that ground went to the ECM and tied into the heater blower ground. On the older vehicles the heater blower ground frequently suffered from melt down at the connection right by the ECM and the blower resistor.

I was told that if you had overheating at that connection it was a possible sign that the heater blower was on it's way out and using to many amps to run.

I'll follow the ground wire for the blower and see where it goes. Don't know about the ground heating up but the red hot wire showed definite signs of heating to the point I was considering replacing a chunk before I buttoned everything back up.

 

[packratt]

If you pull the lower intake remember 4 of the bolts take sealant on re-install - I think the stud with all the grounds going to it is one of the intake bolts that takes sealant

If you have to pull the S intake, I would try to find an F intake to re-install. I would not install an S intake unless I was in a bind for time

I've pulled the intake on the K3500 more times than I care to remember. Don't even have to think about what size the socket is any more.

The S intake had already been swapped for a N/A non EGR HUMVEE intake by the previous owner.

 

[jrsavoie]

Haven't added any grounds other than a battery to fender that was missing.

I don't like the looks of the braided firewall to frame and block to firewall. Will replace them and add one from battery to rear stud.

I also add a ground from Battery to the ground strap on the frame. If you were ever to lose the strap from the block to firewall, you are still grounded from the other direction.

If you have done the battery bolt mod - I use an 1 1/4" Stainless Allen screw with the end going in the battery cut flat. I find it easier to just remove a nut and washer than to jack around removing the whole bolt.

 

[Husker6.5]

What component does the wire going to that ground go to? I pulled the PCM box out and can't find it. Looking through the glove box the heater box goes up to the top of the dash and over to the passenger side wall.

Unfortunately I probably did have a 57 in the first mass of codes where I thought I got off count in the 50s. It never reappeared after I cleared them the first time.

Above the blower housing to the right side of the glove box. You haven't set any codes since because you haven't gotten the engine running.

 

[packratt]

I must be blind because I'm not finding that ground, unless view of it is blocked by the tray the PCM sets in. Didn't have much time tonight to look and would have needed to do some major digging to find a wrench to remove one of the mounting screws that hold the tray.

I'm leaving town tomorrow and won't be able to work on the truck again until Wed.

 

[Husker6.5]

Guys, somebody want to help him out, as I don't have photo capability at the moment?

 

[jrsavoie]

Does your heater blower have a ground?

All of the 6.5's I have worked on have had a ground on the heater blower. But I have heard that not all of them do.

If I remember right, you should be able to follow that ground up and trace it until you get to the other ground

I use a variety of tolls to get in there to change the resistor pack. I know I use the cheap little ratchet from the parts store cheap bins - It is a 1/4" hex drive to run the little bits and my 1/4" Craftsman battery ratchet.

I have never actually had to mess with the ground to the firewall inside the cab.

I have had to rebuild / fix the connection to the heater blower. If that connection has heat damage, it is likely that your fan is shot and overheating the connection.

Fixing that bit of wiring and adding the ground from the heater blower to the dash mount bolt, just inches away - Need a good 5/16 eyelet - seems to achieve the same result.

 

[Husker6.5]

When I get home from work tonight, I'll dig out my GM Factory Service Manual and post photos of the page that shows the elusive location of the passenger side interior firewall ground.

 

[packratt]

THANK YOU

 

[Husker6.5]

This is the verbal description of the elusive G202 grounding point.

 

[Husker6.5]

And here are the various circuits that ground to that point, G202, four pages of schematics worth.

 

[Husker6.5]

And here is the butter, the line drawing of the location of G202!