Battery Fuse In Fusebox Has Voltage On Both Terminals

CFD Jerry

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This will be long so grab something with caffeine being a weird wiring problem…

My airbag light came on and message center comes up service airbag after start up knowing it does a system check twice looking for faults. Originally B1000 (front left/drivers side) front end sensor performance was the only code I had. Both front sensors have different part numbers and found out GM knew one was junk and replaced it with the other part number for a matched set with same part numbers. My guess when manufactured they cleared out old stock getting rid of all the bad ones why two different part numbers.

Finding out either would work I swapped them out for a test. Still had B0100 and then B0103 came on the scanner too being the right/passenger side both had front end sensor performance now having B0103 (front right/passenger) having both codes now. Airbag disconnect procedure 100% correct and put in both new sensor anyway, checked harness, connectors, used contact cleaner, and all looked great. Waiting for new sensors ABS light came on and got C0268 Pump Motor Circuit Shorted, weird thing is B0100 did not come back and never has, but B1001 came being option configuration error once ABS light lit up on dash with some of “U” codes being U1016 Lost communication with ECM, PCM (Vehicle Control Module), U1041 Lost Communication with ECBM, U1064 Lost Communication with BCM. At random get the dreaded U1000 Class 2 Data Link Malfunction and just got at random again U1301 Calls 2 Data Link High. Been poking away at it during my spare time and know had some other codes that showed and never came back.

I know for sure I have a wiring problem checking and finding a short to ground. Negative battery terminal disconnected and off to the side not touching negative in battery. Test light to negative terminal and clip to any ground test light lights up (positive still connected). Confirmed with digital multimeter to see what voltage was with negative terminal off battery to the side and just less than battery voltage.

So for sure I have positive going to ground doing this.

Next had test light on negative on battery (negative terminal still disconnected) test light clip to negative terminal, test light lighting. I learned do this and pull every fuse one at a time until test light goes off. It never did even on inside fuses.

Confirmed all fuses good with digital meter.

Next test. Checking across terminals fuse block with battery connected (both positive and negative) have voltage on both sides of radio fuse with battery voltage on one side and about a .30 drop in other side. Disconnected negative terminal again (only positive connected). Continuity is across radio fuse and using test light on negative terminal off battery (positive connected) any ground or metal touched with clip test light lights.

So I know I have a positive wire going to ground somewhere to do this and have no blown fuses.

I know radio is in with the Class 2 Data and checked Data Link Connector which has 4 Pins. One being one for positive to scanner (has battery voltage), chassis ground terminal and signal ground grounds are good. Confirmed that with digital meter right to negative on battery and ohm out perfect. Data Link has less then 1/2 volt and know it should have 5 volts.

That explains my no communication with vehicle to scanner with above codes and cannot clear B0103 & C0268 quite sure due to that is when all the “U” codes come up. Forgot that from it sitting doing an ABS and Airbag diagnosis with scanner that has it only get “fail” on airbag giving B0103 and ABS passes with no code.

Went to Splice Pack SP 205 and pulled comb out knowing they can go bad and to check voltage, jump out from 5 Volt Reference to BCM to see if I scan tool would communicate with BCM and it will not.

I did put an aftermarket radio in thinking even with getting harness kit not to cut factory connectors, soldering, and shrink tubing all wire’s something is causing it there. Nope all is good and with radio out all the above problems.

With tearing the front all apart under dash found a black connector going to what I can’t find the name of part anywhere that can have 6 terminals, but only had 5 wires all wires torn off it.

I believe this part but not sure that looks like a pump/ solenoid on brake pedal is for the adjustable pedals. To dark to get picture that is clear and had a purple, orange w/black stripe, white, pink, and looks like brown w/white stripe (hard to see faded) going to it.

Checked voltage on all wires and only purple and orange w/black stripe had very low volts checking them on a confirmed ground that is good.

Checked continuity on all 5 wires and purple and orange w/black strip had continuity to each other. Of course those two travel up behind instrument panel cluster and pulling that GM has that blocked off with a plastic panel and may have to pull dash next.

Does anyone know what the official name GM calls what is mounted on the brake pedal with this connector going to it with those 5 wires? Need to replace it, but can’t find it anywhere.

Radio is out 100% still having factory connectors never cutting into them, but did not pull amplifier having Bose Sound that came with it.

I know the radio circuit is part of the 5 volt low reference signal with all major components. We all know the radio fuse should only have battery voltage on one terminal in fuse block and other side should be zero, but I have voltage with a drop of around .30 volts on that side.

Fuses will blow with a short and feel it is on line side before fusebox having no load why radio fuse did not blow with all this.

This too working on it. Connecting negative battery cable back in battery I did have radio turn on twice with no key in ignition and parking lamps one time. Did have a relay chatter when parking lamps went on that one time but so fast could not feel which one. Last night a relay was chattering longer and felt and think it was parking lamp relay, but parking lamps did not turn on.

Weird problem I know and had it to a mechanic and he said he was going in circles with nothing adding up with everything checking out. I would say he didn’t pick up on negative battery cable having voltage to ground disconnected or that connector that had the 5 wires torn off somehow.

I just got one of those cheap testers the phone and internet companies use to check wires. Checks for short to ground (I already know), open circuits, wire tracing and wire identification. Always wondered how they found bad wires out of thousands so fast and this is the tester. Sender has 2 wires with clips on it that you put on suspect wires that are bad. Probe with it you run along wires or try to find wires and it emits a tone that gets louder when right on them and fades away when you get to far from them. Cool how it does it putting a signal on wires the probe can emit a tone when by them picking up that signal from it when you have no clue where they go when you can’t see them being hidden.

Hoping that the 5 wires that came off that connector is the problem 100% and didn’t just find problem 2 on it.

Anyone ever have this problem before find radio fuse with voltage on it like above, no 5 volt reference signal, and some “U” codes not showing on scanner every component on 5 volt reference all down and only some?

Plus, what is that part in brake pedal officially called by GM with no luck finding it on any search with those 5 wires on it????

Sorry so long and know wiring problems are the hardest things to find knowing how one or two bad wires can cause havoc on something, but once you find and repair all good again. Just like one bad ground can do the exact same thing too, and on regular maintenance or weird problems that all come at once and then more a bad ground can be the cause. I had it in the past losing a ground up front 100% all weird things going on and dash lights galore where nothing had any rhyme or reason with no trouble codes.

Check all your chassis ground with a digital multimeter and if you have to add wire to a lead do it and go right to battery negative on all of them.

You never want over 5 ohms checking them and we were told in school for grounds remember “Ground Zero”

Once found and fixed wondering if PCM, BCM, and EBCM got fried from this.

Suggestions or thought? Plus, what is the pump looking part in brake pedal with that connector officially called?

Going back at it now that this tester came and will update.
 
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CFD Jerry

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Once again sorry for being so long and know I put in some repeats typing so much. That connector under dash with 5 wires ripped off I know need to be fixed for sure and all of them traced and checked where hoping short to ground is coming from.

I do have the 10,000 page plus factory service manual and once I know what that part is once I read wiring schematics. If I can totally disconnect those wires for a test until connector fixed or re-wire it all in brand new.

Thanks for reading and hoping for some help.
 

Donal

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Well. not sure of your vehicle? major revision of elect stuff 2003 or so. looked through 315 pages. does veh have trailler brake controller? i not good with colors either. need more data and time. Are you close to Pine Hollow?
 

MassHoe04

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Fuses will blow if current exceeds the fuse rating.
If a short happens on the line side of things, the current never makes it to the fuse to make it blow.
Hopefully, there is a bigger main fuse upstream on the line side of whatever might short, to protect the line from arcing out with the full current from the battery...

Maybe something inside the BCM is shorting? That could blow fuses on various sub-systems/accessory circuits and also make things act weird or not work at all.
 

Fless

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Once again sorry for being so long and know I put in some repeats typing so much. That connector under dash with 5 wires ripped off I know need to be fixed for sure and all of them traced and checked where hoping short to ground is coming from.

I do have the 10,000 page plus factory service manual and once I know what that part is once I read wiring schematics. If I can totally disconnect those wires for a test until connector fixed or re-wire it all in brand new.

Thanks for reading and hoping for some help.

It's been over a month since this was posted, and a month since the OP started the thread. OP, has this been fixed? If so, would you care to share the solution?

Might be helpful to know the make, model, and year so we know which year electrical system is being worked on. Help us out!
 

OR VietVet

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@Donal and @Fless and @MassHoe04, I read and read and read and read and thought that eventually would get the OP to tell us what he/she is driving. Never did. IMO, that is amazing after seeing all that was shared about the problem but no sharing of at least the basics of, "What in the name of the Wide Wide World of Sports" are you driving for criminy sakes!

But I guess we all know that all the tahoes/Yukons/Escalades from 2000 to 2006 are ALL THE SAME. C'mon man!

Then, to not get back on what is going on, again, c'mon man!
 

Donal

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Once again sorry for being so long and know I put in some repeats typing so much. That connector under dash with 5 wires ripped off I know need to be fixed for sure and all of them traced and checked where hoping short to ground is coming from.

I do have the 10,000 page plus factory service manual and once I know what that part is once I read wiring schematics. If I can totally disconnect those wires for a test until connector fixed or re-wire it all in brand new.

Thanks for reading and hoping for some help.
I see seat wiring info on pages 296 and 297. Not sure if you have the same manual edition.
 

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