1985 K10 Suburban 6.2 won't shut off

[Cwilburn355]

My son bought his first truck. While installing a radio we noticed two fuses missing. The 20a Ign/Guages and the 15a Radio fuses were pulled we replaced both and everything seemed fine. We drove the truck and everything worked until we went to shut it off. The truck kept running until I pulled the Ign/Guage fuse. The truck shut off and then starts back up no problem. Has anyone had experience with this issue? Is there anything we can do to "fix it" and leave the fuse in? Thanks in advance.

[DmaxMaverick]

Welcome aboard!

The Ign. switch/linkage is failed or the electrical is hacked. You'll have to do some old-fashioned wire chasing to find out which, and what to do about it. I suspect it's probably the Ign. switch, its linkage or wiring, as pulling the Ign. fuse shuts it off. The downstream wiring should be OK. Check under the dash for anything that looks like wire splicing and such. If you need a 1985 electrical diagram, I have one. Send me an email (in signature below) and I'll reply with the diagram files. They are scans of the original, not very good, but readable.

It could also be the rack and pinion or connector that operates the switch (located on the left side of the column). Once you drop the column, turn the key in both directions and make sure the rod moves the switch fully. If the rack and pinion or connector needs replacement, you'll have to disassemble the column, starting at the steering wheel end. All the parts involved should still be common and available.

If you have to replace the ignition switch, it isn't too difficult. It's on the column behind the instrument panel bezel, connected to the lock cylinder with an actuator rod on the opposite side. The column, once the mounting nuts are removed (remove the lower trim panels first), will drop down enough to access it. The switch may be different depending on options (I don't recall --it's been 20+ years), so make sure you get the correct switch for either tilt or non-tilt column. The dimmer switch is also rod actuated on the same side, but I don't remember if it has to be removed first, or if it didn't matter (check it for operation, and replace it if necessary while you're in there). There's probably something on Youtube that can be helpful. I think they were the same for all square body trucks through the years, with the only significant difference being tilt or non-tilt columns.

[Robyn]

If you need the rack and pinion assembly that runs the switch....these are available at most auto parts stores.

There are kits available with the new plastic housing that the signal switch sits in as well as the rack and pinion parts.

I would disconnect the large pink wire at the injector pump and connect it to a light tester......then start fooling about until you find the issue.

The large pink wire should only be hot in ON/START

Ignition switch possibly or as Maverick described the linkage or all the above..

As these rigs get older the more stuff gets hacked and or just wears out.

Somebody could have messed with stuff wiring up something and ended up with the gremlin as a result.......

[Cwilburn355]

Thank you for the guidance. Will this still allow the truck to start back up even with the fuse pulled?

[DmaxMaverick]

No. Unless you bypass power to the IP fuel solenoid, it will get no power. Repairing it will allow you to start and stop with the fuse installed, as it was designed. You have to pull the fuse to stop it because, for some reason, turning off the key is not stopping power to the solenoid. What happens, while it's running, if you turn off the key and continue turning it to Acc. (all the way back past off)? Does the instrument panel and HVAC shut off (gages and lamps no longer respond, fan stops blowing)?