New Suburban already broken

Maybe possibly unsure.

Or it could have been an intermittent fault - the most PITA kind, since 75% of diagnosing one is duplicating the issue.

it was... the computer was looking for resistance from the light and not finding it before.

I had this happen on my Cadillac years ago, turned out one of the shock sensor (it had the rheo-super-magnetic fluid filled struts) wires was broken leading to an open short on the circuit. This would turn on the traction control off light, ABS warning light, Brake warning light, would speed limit the car to 90 MPH, and lockout 1st gear on the 4 speed auto-tranny. I thought all GM cars with the MFDs act as an OBD display (my Cadillac did) and with the right sequence of dash buttons you could get the error codes off the various computers to tell you exactly what the problem is...

Mazdax605 wrote: Could it have been that light not being present?

In my non-professional opinion it was definitely caused by the light being unplugged.

mad_machine wrote: it was... the computer was looking for resistance from the light and not finding it before.

+2. From an automotive computer standpoint it makes sense that the computer was "expecting" there to be a draw or a completed circuit and saw none.

From a non-automotive standpoint, too coincidental to not be at least the accepted cause up until it happens again.

Hell, take out the light again and see what happens...

EDIT: See Mad_Machine below!

um... how many times did I say it was the light?

Even without know how it all worked... if you made a change to your vehicle and it suddenly stops working normally... what is the first thing you look at... the thing you changed

not a GM, but when I tapped into the tailight switch for my power commander install it freaked the computer out on my BMW k1200s. I changed it to the license plate light and all was well with the computer again.

Mazdax605 wrote: So now I am confused. I got up early this morning, and put the burned out high-mounted brake light back in place, took the truck for a ride and no lights on the dash. Thought well maybe it will come back on again, so I drove over to my friends house that has a really nice professional scan unit. Still no lights. Didn't scan it due to no warning lights. Could it have been that light not being present?

Did you read the first response in this thread?

Hal wrote: I would start with replacing that light. With the way the systems are in newer cars the absense of the light even though it was burnt out may be the cause of the problem.

Mazdax605 wrote: So now I am confused. I got up early this morning, and put the burned out high-mounted brake light back in place, took the truck for a ride and no lights on the dash. Thought well maybe it will come back on again, so I drove over to my friends house that has a really nice professional scan unit. Still no lights. Didn't scan it due to no warning lights. Could it have been that light not being present?

Absolutly. I am suprised that onstar did not call you and tell you that your brake light was out.

mad_machine wrote: um... how many times did I say it was the light? Even without know how it all worked... if you made a change to your vehicle and it suddenly stops working normally... what is the first thing you look at... the thing you changed

That is troubleshooting 101 right there.

I just thought it odd that the warning lights came on quite some time later. Why not come on immediately after I started the car up,and not 20 minutes later?

My thought was why would it matter that the burned out light be there or not. Either way it isn't working.

My dad had a Chevy Express of the same age with exactly that problem. After repeated trips to the dealer they never did figure it out. It happened on and off for the rest of the time he had the truck (until about 150k miles) and every time he would just shut it off and turn it back on again and the lights would go away.

I have an 04 suburban that is doing the exact same thing intermittently. It sounds like the world is coming to an end with all the buzzers and lights and then the next time I shut it down and re-start, lights are out and ABS works just fine. My wife found out that panic stopping when the lights are still on gets rear brake lockup. We have taken to stopping at the next available safe place and cycling the ignition so that we will have ABS if needed.

Someone prior to me has been cleaning grounds all over the bottom of the Suburban trying to chase the problem...I found when I started to look more carefully.

I'll check the wheel bearings & ABS sensors. Our 3rd brake light work.

Have you checked the brake fluid level ?

Besides having the ABS sensors checked, also look at the wiring. My dad's Buick Rendezvous has a similar problem where the traction control goes crazy on him sometimes. A known issue with the Rendezvous is that the ABS sensor wires were too short from the factory and have a tendency to stretch out over time. This leads to iffy contacts and sometimes corrosion thanks to the wires being exposed. He's been to the shop 4 or 5 times to get it fixed and even had the hub/sensor assemblies replaced twice (one with aftermarket parts, once with GM parts), but the issue still comes up intermittently. Dad plans on replacing the Rendezvous later this year, so he's given up on fixing the problem entirely.

All front drive based GMs have ABS wiring problems. The wires flex too much because of where they are routed (BAD routing idea, GM. Bad.) and break down a couple inches from the connector, or saltwater collects there and corrodes the snot out of it. It's common enough that there is a repair pigtail that comes with about four feet of wire and explicit instructions on the correct length for whichever chassis.

This isn't counting the wring problems that some J/N bodies have under the battery box.

I'll take any of those problems over the issues VW is having with the ABS unit drawing too much current and taking down the CAN. The ABS activates (including traction control) and suddenly the car stumbles, or the transmission shifts inappropriately, or all number of odd problems. Fix is a new control unit. Control unit is buried underneath the master cylinder, in the nook between the fenderwell and the firewall... and this is completely overlooking the expense.

In reply to Knurled:

If you could point me to where I could find the ABS pigtail for a 2004 Buick Rendezvous, that would be great. I knew something like that had to exist, but the local shop my dad goes to didn't. Also, thanks for reminding me why I'll NEVER own a modern VW.

I forget if we get them from the dealer or if it's a Dorman thing. But, they're definitely available, ABS faults on these cars are almost always broken wires, and the rest of the time it's a bad wheel bearing.

Might be called a repair harness and not a pigtail.

Here, found this for you: http://www.dormanproducts.com/gsearch.aspx?&type=keyword&q=abs+inmeta:parttype%3DABS%2520Wheel%2520Speed%2520Sensor%2520Wire%2520Harness&dnavs=+inmeta:parttype%3DABS%2520Wheel%2520Speed%2520Sensor%2520Wire%2520Harness

Dorman (aftermarket) numbers as well as the OEM numbers that it replaces. Should come with the awesome crimp-n-shrink connectors that I love so much. (Srsly, it's all we use at work. I did my Megasquirt harness with them and have had zero wiring issues after 4 years and many engine swaps)

Thanks, Knurled! I'll show that to Dad. Not sure if he'll replace it, but it's good to know the part is out there.