This brake problem discussed is one possible problem of several, but is the source of the problem very frequently, about 95% or more! The other internal problem could be a relay, or there could be a ground issue, associated part, etc…. BEFORE you remove the ABS unit for repair, please check the vehicle ground cable located near the ABS under the driver seat that bolts to the frame of truck for rust and proper tightness. Remove and clean just to make sure, I know several people that have removed and spend money on an ABS repair, only to find out the ground cable was loose.
The Kelsey Hayes 325 Electronic Brake Control Unit (or module) on the SSR (and many other GM vehicles) is prone to solder joints cracking due to poor solder from the factory. There is some speculation that the issue is related to heat since the SSR location is near the catalytic converter, but this same issue happens to the same generation brake modules that are located in the engine bay near the booster. It also only happens to 12 of the several hundred solder joints in the unit as shown in red circles in image below. If it were a heat related problem, the issue would not be isolated to such a small percentage of the joints and would be more scattered across the board. While there is no doubt that the aftermarket heat shield does keep some heat away from the brake module, it is unlikely that it will prevent this issue from occurring.
The unit is located under the truck against the frame, under the driver seat area. To get the unit repaired, just the top part of the unit is taken off, 3 electrical connectors and 4 bolts. DO NOT remove the hydraulic lines. To make it a little easier to access the top bolts, remove the bolts that hold the ABS mount to the truck frame. This will allow the unit to be pulled out and down just a little. You can drive the truck with this unit off, you will not have any ABS function though. Due to this fact, it is not recommended to drive for an extended period of time, but getting home from the mechanic or a quick trip to the store should be fine as long as it is not raining or very dusty, those circumstances would require some sort of covering to prevent dirt and moisture from entering the pump housing. Make sure you cover the exposed open area on the truck mounted pump when you take the control unit off with aluminum foil and some high temp tape to keep dirt out.
After the unit is removed. Be VERY careful taking the cover off, there are components lining around the edge of the interior. I have repaired a few units people really banged up but not all can be saved. I use a heavy duty razor blade to cut around the perimeter several times to break the sealant, then I carefully take a screwdriver to wedge it in a pry the top off. Once off you will see the board, below in red are the areas that are problematic and need high quality solder for repair. The yellow areas below show thermal bonding paste points that need to be taken care of. I have seen some people use RTV on these spots, DO NOT DO THAT!!!! This material is for a thermal transfer and needs to allow the heat to transfer. If anything, use some computer thermal paste if it is completely gone to replenish the bond area.
Once resoldering is complete, use a high temp RTV to reseal the cover to EBCM, allow to dry and reinstall.
Companies that offer repair –
Module Master – https://modulemaster.com/rebuilds/
If you are going to attempt to purchase a used ABS Control Module for the SSR please note that there are many variations of the Kelsey Hays 325 module, and that they are not interchangeable. The one use on the SSR needs to have traction control as an internal function. The OEM part numbers are different for the early and late models.
- 2005 -2006 – (GM rebuilt 19245462, 19301637 )
- 2003-2004 – 13451136 (GM rebuilt 19299980, 19299676 )
In closing, I have had to repair several poor attempts at a repair by other people. Please do NOT do these things –
- Do not force the cover open hard enough to bend the case, if it is still attached that well please continue to carefully use a knife edge to cut into the sealant around the perimeter.
- Do not insert the blade of a knife or screwdriver more than 1/8 of an inch into the sealed area, there are components lining the circumference and pushing in too far could damage something.
- Use a good solder with flux to clean the connection and use a proper temperature controlled iron.
- Do not remove the pink heat sink thermal compound or replace it with RTV. If needed, you can sparingly add more thermal compound, the same used for computer CPU installations.
- Make sure you remove all of the OEM sealant before you seal it back up. If you to not remove all of the old sealant from both sides of the parts you will not be able to properly seal it back up. Small gaps will be there and there is a high probability of moisture entering.
Above is a destroyed component from someone that opened the case wrong. I sourced the chip and repaired it properly for the customer.