ABS Light, Parking Brake Light, Service Brake System, No speedometer

[jbaas14]

Sorry if this has been covered elsewhere, I used the search function and was unable to find anything.

This happened once last week and went away, but today had to leave the TB at work because it isn't drivable.

The ABS light, parking brake light and service brake system warnings are all on, the speedometer is not working, and the blower speed is lower than normal. When accelerating the car just doesn't want to go, no shifting, no power. Brake fluid is good, pads are good, will check for codes tomorrow when I get back to it with a reader. Had the transmission replaced a few months ago, could it be a speed sensor? Ignition switch? Something else? Any feedback as to what to look for first is greatly appreciated!

 

[HARDTRAILZ]

I thought ignition switch, but it is starting ok?

How does it idle and does it hesitate to rev up when just sitting still?

 

[The_Roadie]

I'd be highly suspicious of a ground issue.

Start by inspecting/cleaning/tightening G201, discussed here:

http://gmtnation.com/forums/topic/11054-help-with-4x4-service-4x4-light-and-selector-lights-on-sometimes/

The main four to look at, but you should inspect everything you can, are the transmission tunnel master ground, the ABS controller ground on the frame rail under the truck underneath the driver's seat area, one on the side of the engine block, driver's side, and the body ground on the fender near the battery.

 

[jbaas14]

I thought ignition switch, but it is starting ok?

How does it idle and does it hesitate to rev up when just sitting still?

It seems to be starting just fine, never really have an issue there.
Idle is rough, and worse when A/C cycles, typical TB stuff right? (I routinely clean the throttle body) It seems like it does hesitate on occasion when revving at a sit still and on occasion will stall when coming to a stop.

I'd be highly suspicious of a ground issue.

Start by inspecting/cleaning/tightening G201, discussed here:

http://gmtnation.com/forums/topic/11054-help-with-4x4-service-4x4-light-and-selector-lights-on-sometimes/

The main four to look at, but you should inspect everything you can, are the transmission tunnel master ground, the ABS controller ground on the frame rail under the truck underneath the driver's seat area, one on the side of the engine block, driver's side, and the body ground on the fender near the battery.

I looked at all of the grounds in question and they all appear fine with except for the ABS controller ground. When I tried to get the bolt out it busted it was so rusted. I drilled the rest of the old bolt out and put a new ring terminal on the cable, sanded the crud off the frame so it was nice and shiny. After all of that, the only change is if I push the ground wire into the frame and hold it, the light will turn off momentarily and then come back on.
My code reader is dash command for iPhone with an elm bluetooth obd, so I don't think it will read any ABS codes...