Sounds like it appears to be an issue with your control module. I would suggest looking at the local junkyard and finding one to replace yours with. This happened to my 88 c1500 and as soon as I replaced it, all was well.
It may also be worth making sure the ground for the rear lights is still tight and snug to the frame. Had to take my bed off to change rusted brake lines over the weekend and forgot to re-ground the rear lights to the bed frame and had a similar experience to you.
Good luck.
I have recently had this same issue in my 98 Silverado. I ended up still having air in the rear brake lines. It took a while, but eventually after bleeding the brakes a second round it fixed it self out.
The only issue I am having with the truck is, it runs really bad when I turn the heater on and I cannot figure it out. I have looked all over the place(google) and all links point to Trailblazers.... lol.
Any help would be awesome.
Hey all! Semi new to the site.
Below is my 88 Scottsdale, it has the 5.7 V8 TBI engine in it. Basically stock and plan to keep it that way.
Was a gift from my friends dad, he let it sit for about 6 years and I have been in the process of restoring it back to the way it should be.
This...