1999 GMC Sierra 1500 ABS malfunctioning

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Aug 4, 2021
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1999 GMC Sierra 1500 4x4

Abs and brake light randomly comes on dash and even a feather landing on the brake pedal can cause wheels to lock up. As soon as I turn off the car and restart everything is back to normal. And the lights can return in a few minutes or a couple of months. And sometimes turning of the car and turning it on multiple times doesn’t work and sometimes taking out the fuse and putting it back works but no ideas if that’s a coincidence. I replaced fuse but keeps doing it. Any help would be greatly appreciated and I’m very much hoping it’s not the whole abs module
 
I had a 2002.
I had to take the abs control box apart and re Solder
You see what connections were broken loose.
Used an eye loop.
All fixed no more issues after that.
This is a known problem on those models
 
1999 GMC Sierra 1500 4x4

Abs and brake light randomly comes on dash and even a feather landing on the brake pedal can cause wheels to lock up. As soon as I turn off the car and restart everything is back to normal. And the lights can return in a few minutes or a couple of months. And sometimes turning of the car and turning it on multiple times doesn’t work and sometimes taking out the fuse and putting it back works but no ideas if that’s a coincidence. I replaced fuse but keeps doing it. Any help would be greatly appreciated and I’m very much hoping it’s not the whole abs module
Unfortunately it is the ABS module. The solder begins to break as they age. The module sits on top of the frame rail on the drivers side. It can be a bear to get off. There are companies that can take it apart and resolder it so there is no need to buy a new unit.
 
Sounds like the ABS module (EBCM). The good news is I think it's plug & play on these and it is readily available aftermarket. Had to get one for an 04 Sierra delivery truck at work a few months ago.
 
Unfortunately it is the ABS module. The solder begins to break as they age. The module sits on top of the frame rail on the drivers side. It can be a bear to get off. There are companies that can take it apart and resolder it so there is no need to buy a new unit.
Can a bad connection or dirty connection cause the problem? I offroad and mud bogg the truck regularly. I havnt looked under there yet but I never wash after off roading
 
I had a 2002.
I had to take the abs control box apart and re Solder
You see what connections were broken loose.
Used an eye loop.
All fixed no more issues after that.
This is a known problem on those models

Would this be the same for any other GM car of the era, like my 1999 Alero? Because I have never heard of this before.
 
Can a bad connection or dirty connection cause the problem? I offroad and mud bogg the truck regularly. I haven't looked under there yet but I never wash after off roading

At least for my Alero, according to the internet, the contacts where the wiring harness plus into the ABS sensors can get corroded. The fix is to clean them.
 
Can a bad connection or dirty connection cause the problem? I offroad and mud bogg the truck regularly. I havnt looked under there yet but I never wash after off roading
It's possible. Always try the easy fix first but my money is on bad solder joints. It is such a common problem that there are business's that do nothing but resolder ABS modules.
 
Any ABS codes? That's the first step to see what the system is seeing. Hubs going bad can cause false activations, bearing may not be making noise at first.
My '99 Yukon had rust swelling around the sensor on the outside of the hub causing its gap inside to increase and false ABS actuations. Even with a new sensor. Ground the rust off fixed mine one wheel.
Bearings in my hubs were good, just exterior rust swelling.
200k on my module and no issues with it, only sensor issues.
 
Oh yeah I saw the YouTube videos. Everyone says it’s the soder that corrodes and gets brittle. I’m going to have to get it looked at.
 
Any ABS codes? That's the first step to see what the system is seeing. Hubs going bad can cause false activations, bearing may not be making noise at first.
My '99 Yukon had rust swelling around the sensor on the outside of the hub causing its gap inside to increase and false ABS actuations. Even with a new sensor. Ground the rust off fixed mine one wheel.
Bearings in my hubs were good, just exterior rust swelling.
200k on my module and no issues with it, only sensor issues.
No codes. And hubs are new. Can rust on one cause all wheels to lock up when the abs goes out?
 
Can a bad connection or dirty connection cause the problem? I offroad and mud bogg the truck regularly. I havnt looked under there yet but I never wash after off roading
Yeah, it could also be due to the truck being 23 years old, or both. You could try disconnecting the battery, hosing the connectors with connector cleaner (not electrical parts cleaner, you need the stuff for connectors). Let it dry out completely, and if it doesn't work you probably need the EBCM. If you send me the VIN I'll give you the EBCM part number so you can cross it at a parts store. This is not a diagnosis, just a suggestion based on past experience with a similar truck.
 
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