you are using a wiring diagram to analyze this huh?

 

Thank you 06PullUout
So far this week we have tried 4 new Sylvania bulbs on the rear, 2 new to each side, with no results. Doesn't mean we can't try a couple more . . .The Sylvania's are cheap compared to other options, so what the heck.

Though next we'll try a common volt meter to rear, if we can seperate out turn/brake on socket from running, to see if any power getting there, though we're pretty sure none is.


DrTom
As far as wiring diagram goes . . Even the factory service manuals (2 book set) are extremely vague on these. I could find the schematics of the harness to front headlights, radios, antennas, but not to rear lamps. Though admit reading correctly could be operator error. Admit also to being a simple laymen, most certainly not ASE cert. tech. Heck I'm a flooring tech!! This is why I ask so many questions here, even if many of my questions are dumb and why I search blurry eyes across the net, All in hopes of connecting with those who have answers in areas I do not.

We also did some general Google searches of this issue we have on our H3, pulled up a only a couple that had BCM issues listed as final fix.
This seemed a rare answer to issue. But then so was the odds of our complete engine shelling out at 70K even though that's what seemd to have happened. And it was.
And so we were told was our radiator issue, until I posted here.
I now take nothing for granted.

Going back through the factory manuals . .sec 11 pg 122 under 'wiring systems' states that Fuse #20 is REAR TURN/HAZRD FUSE 20A with a description as 'Body Control Module (BCM)' The fuse is good . . . looked good physically but replaced still nothing. Tested old was solid.
Back in the manual . .under 'Turn signal lamps and / or indicators inoperative' Sec 4 page 200 We do not have the precise diagnostic testing tools, asked to use, (we know a major handicap with electrical issues!) Basically as you go down the line you just keep swapping out components! first the IPC module then the multi switch then the BCM. As you go down the line if you can not find a loose connection . . . ICP has display and sound, then step . . .11 replace turn signal / multifunction switch (Which we had already done as our 1st hope / assumption after chasing wires in visual range) Book then says If you have completed this repair and did not fix issue next change out BCM.
So we're here groping in the dark, adding 2+2 we come up with BCM is in series in this circuitry. We'd sure love to hear a simpler, better (and cheaper) answer! This is why I ask questions no matter how dumb. I'm willing to learn!
Thanks always for any help / suggestions.

 

Finally had Tuesday off to run H3 to the dealer . . No Surprises. Issue was exactly what we guessed. BCM (Body Control Module) Once more an issue called rare, hits us. Though a tech at the dealer said he had same thing happen to his so . . .we are not as rare as it would appear.

On a better note . . As we had already checked and replaced most every other guess or component, the cost was not has high as would have been had they started at square one. We managed to get out the door for . . . $632.00, counting our $43 rebate credit applied from our other work done. (Still OUCH) As Zone did have part in stock was actually completed Tuesday night though we did not pick up until Wednesday.

Note to anyone with this issue, keep in mind BCM (Body Control Module) must be installed and more importantly programmed by a GM tech with their special code readers and meters. And access to GM computer site for online programing! And also remember . .to give them all door remotes, faster and easier for them to program remotes while at it. (I had read this needed to be done but almost forgot to give them second one! Realized this when we went to pick up the H and I went straight to unit first and found second remote did not lock or unlock the H.

In any case glad to have it back . . Much as I love our truck So tired of having to drive diesel daily at todays prices fuel prices!

 

just be absolutly,positively,completly,sure,there are no worn or pinched wires near the back bumper. you do not want to rerun this scenario, AGAIN.
i doubt that those modules go partially bad on their own. it still drove the truck huh?
be very careful.

 

Now that we know about pinched wires, (I had so hoped this was the answer to our issue)
This will be part of our regular service like changing oil.
We had unclipped from frame, and inspected all that could be and went over the rest with mirror and flash light.

No we did not dare drive Hummer on these crazy highways! We have been working nearly 30 miles away daily! Would not think of driving something not working fully! Last thing we need is for some crazy to crawl up our back end because we didn't have enough brake lights or they didn't see any turn signal!! (although I heard legally would have still been their fault. But legally don't keep us un-dented!)

Must admit I forget how much more caution other people have when one is driving a big Ram Diesel Truck haha.
With the H (even a baby one,) they mostly have envy "-)