Brake light on but great pedal still

[movietvet]

Drove to get headliner installed in my girl's 1990 K2500. Pulled over to let my friend punch in gate code to enter complex. I set the flashers to work. They did not flash at all. The t/s work fine. Then I noticed the brake light was on. Pedal felt normal/good. Fluid was full. Brake lights are not stuck on. Pull pedal up and no change. Try to set the park brake and the light gets brighter. I suspect and will inspect maybe maybe a problem in the steering column, since the light did not come on till tried to use the flashers. Reset and take off the flashers and still no flash and no change with light. Gonna check out later today or tomorrow. Any thoughts, share them. I will inspect the entire system though. Can't have my girl driving around with a brake light on. Oh, the drive back was no problem at all except for the light being on.

 

[1998_K1500_Sub]

The hazard switch in the later trucks (1994+) has MANY connections in it which are altered when the hazard switch changes position (OFF/ON). I'll assume (right or wrong) that the 1990 switch is similar.

There are a handful of contacts on that switch that can become broken / dislodged, or perhaps corroded, and can lead to really odd behaviors (one GMT400 owner posted that, if he had his foot on the brake when he turned off the ignition, the engine would continue to run... which turned out to be a hazard switch issue). You might be another victim.

If the issue stems from poor contact closure (e.g., due to corrosion), perhaps working the switch multiple times will clear the contacts enough to cause it to function properly, at least for a while.

(edit) Here's a schematic snipped from the 1989 service manual showing the many connections in the turn signal / hazard switch assy. Notice how the hazard "switch" amounts to five switches ganged together illustrated as four double-throw switches and one single-throw.

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[movietvet]

Well, I decided to pull the steering wheel and get a peak inside the column to see if I could see a wiring/corrosion problem. I then ran in to a problem that I had never ran in to before. Removed horn button, removed the little clip at top of stem, removed the stem nut that holds the steering wheel to the stem. I did verify the alignment marks and they were spot on. I figured out the correct 2 bolts to thread in to the steering wheel and set up my puller. Then.....tightened down the center bolt of the puller and that steering wheel would not pull off/pop off. I tightened by hand with a 3/8" flex head 14" MAC ratchet. I reached a point where it was either coming loose or something was gonna break. I backed everything off and when I pulled the two washers off, that were under the heads on the two bolts threaded in to the steering wheel, the washers were bent like they were gonna pull thru the cross bracket. The slots for the bolts to go thru on the cross bracket are just big enough for a 3/8" bolt and the 2 I used were 5/16". It was gonna get dark soon so I put everything back on and shut it down for the night. There was no signs of corrosion or rust on the stem or steering wheel. I know it is gonna come off, come hell or high water, but it is my girl's truck and she is in Texas and due back for the Super Bowl. The truck can stay parked till I talk to her about it. Felt pretty good about getting the headliner done today and then the brake light comes on and now this. *&%$#@*****

If it gets that tight on the next attempt, I plan to use a ball peen and tap the top of the threaded puller bolt head and see if I can shock it.

 

[1998_K1500_Sub]

With regards to the "brake light" OP mentioned in post #1, this information is from the 1989 FSM. FYI, the GMT400 FSMs can be found here: https://www.gmt400.com/threads/88-95-service-manuals.43575/

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and this

You must be registered for see images attach

See the attached for the wiring diagrams.

 

[HotWheelsBurban]

Well, I decided to pull the steering wheel and get a peak inside the column to see if I could see a wiring/corrosion problem. I then ran in to a problem that I had never ran in to before. Removed horn button, removed the little clip at top of stem, removed the stem nut that holds the steering wheel to the stem. I did verify the alignment marks and they were spot on. I figured out the correct 2 bolts to thread in to the steering wheel and set up my puller. Then.....tightened down the center bolt of the puller and that steering wheel would not pull off/pop off. I tightened by hand with a 3/8" flex head 14" MAC ratchet. I reached a point where it was either coming loose or something was gonna break. I backed everything off and when I pulled the two washers off, that were under the heads on the two bolts threaded in to the steering wheel, the washers were bent like they were gonna pull thru the cross bracket. The slots for the bolts to go thru on the cross bracket are just big enough for a 3/8" bolt and the 2 I used were 5/16". It was gonna get dark soon so I put everything back on and shut it down for the night. There was no signs of corrosion or rust on the stem or steering wheel. I know it is gonna come off, come hell or high water, but it is my girl's truck and she is in Texas and due back for the Super Bowl. The truck can stay parked till I talk to her about it. Felt pretty good about getting the headliner done today and then the brake light comes on and now this. *&%$#@*****

If it gets that tight on the next attempt, I plan to use a ball peen and tap the top of the threaded puller bolt head and see if I can shock it.

I think the correct bolts for pulling the steering wheel on the older GM columns are 5/16"-18 coarse thread. I know I used to use a 1/2" socket and nutdriver to run them in and out of the columns, when I used to pull the 70s 3 spoke sport steering wheels off....
You might try the hammer smack on the puller shaft, sometimes a joint that's been together for years needs a shock to break it loose. Might also squirt a little bit of penetrating oil on that main shaft....

 

[movietvet]

Thanks for this info. I can have some fun now.

 

[movietvet]

I think the correct bolts for pulling the steering wheel on the older GM columns are 5/16"-18 coarse thread. I know I used to use a 1/2" socket and nutdriver to run them in and out of the columns, when I used to pull the 70s 3 spoke sport steering wheels off....
You might try the hammer smack on the puller shaft, sometimes a joint that's been together for years needs a shock to break it loose. Might also squirt a little bit of penetrating oil on that main shaft....

They are 5/16" course thread. I forgot to spray some penetrant on the stem but removing the horn button for access, is a 2 second job.

 

[movietvet]

Well, all I had to do was stop over thinking the problem. Because it did not happen till I pushed in on the hazard light switch, I assumed the worst but I was wrong. Turns out that it had 2 simple problems. The 2 prong hazard flasher had a corroded prong and there was a 10 amp brake light fuse that was blown. I replaced the flasher after cleaning the female connector and since the radio does not work and takes the same 10 amp fuse, I swapped it in the slot and now the brake lights work, the hazard flashers work and the red brake light at the dash is out and does it's self test when I start the vehicle and goes out. All good now. Apparently, I was in a rush on the headliner and did not check for brake lights at the shop yesterday and drove home with no brake lights. All good and only cost for the flasher.

 

[GoToGuy]

First rule of electric trouble, did you check the fuses? " Doh! "

 

[movietvet]

First rule of electric trouble, did you check the fuses? " Doh! "

Completely agree and that is why I posted as I did. In the heat of the moment and the excitement of getting the headliner in, I did some quick checks and made assumptions and mainly worried about pedal feel and master cylinder fullness, to get home and check there, where my tools are. Raining when got home and was running thru what took place to turn that light on. It all started with trying to turn on the hazards. At the headliner shop, I did not look to see if brake lights came on. At home, I did and when there was no brake lights, I went right to the fuse and found that problem but still no hazards and went to the flasher and found that problem. My brain did not settle down away from tools but when home, I did do nothing but the basics first.

But, man that headliner looks good!!!!