Any Chevy/GMC techs ?

My '86 GMC p/u has developed a problem with the ignition switch assembly ... it'll turn on , but win't go past that point to the start position . I'm pretty sure there's an interlock in there to prevent engaging the starter when in gear but I'm not sure if it's down the column in the switch or up in the top end begind the steeering wheel . Anybody know where it is and what I'm likely to break getting at it ? I have the steering wheel off already , and am about to fab a tool to pull the lock plate .

Reply to
Terry Coombs
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If it has an automatic transmission then there may be a interlock switch on the shift lever to prevent starting when the transmission is not in the park position.

Reply to
nobody

Well , thank you very much . Did you miss the part of my original post quoted above ???

Yes , I know there's an interlock . I just ain't sure where it is . Could be integrated into the switch assembly down on the column , could be up in the shifter area . I have it partially stripped , next step is to drop the column - unless it's in the upper part , which I can disassemble without dropping the column . The hell of it is that the problem is probably nothing more than a screw that didn't stay tight ...

Reply to
Terry Coombs

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Reply to
PrecisionmachinisT

86 doesn't have an interlock. Those didn't start until 1994 on the trucks.

The switch is mounted down on the column under the dash. Reach down there and see if it travels fully when you push it. I will almost bet it won't. The contacts break and block the switch.

If it does move OK. Then the next likely item is that the rack or cylinder gear have failed. They are both pot metal but the rack is usually the thing that fails.

Reply to
Steve W.

Thanks , looks like I'll be going all the way into the mechanism . This truck was stolen from the last owner , they smashed the column . The rack and all that SHOULD be new ... I can't get to the switch assy until I drop the column , so any way it goes I won't be making it to that appointment to have the front end aligned . At least there's an upside , if I need parts I gotta ride the Harley to get 'em ,

Reply to
Terry Coombs

No real help here. But you could look at the electrical diagrams and figure out how to add a separate push button switch to engage the starter. Not as safe as repairing the original switch.

Dan

Reply to
dcaster

That's 1 year after I got out of the biz.

It's probably in the upper portion of the column, unless it has one of the long 1/8" rods to interact with a switch in the middle of the column.

Pop the dash cover plates and look at the column for funky rods which move with the switch position. If you don't find one, pop the wheel and turn signal ++ switches and go from there.

OR, call the dealer tomorrow morning at 8 and ask them precisely where it is. They have (usually Mitchell) manuals with the info for each year and model. Ditto the parts counter at the dealership. Some service managers want you to come in, but the parts guys will talk to you about it for awhile. Their exploded diagrams are excellent for finding out how something ticks prior to tearing into it.

Reply to
Larry Jaques

I can't comment on American cars but on the Asian - Toyota, Honda, Isuzu, the interlock isn't mechanical it is an electrical switch and on the cars I've seen it was on the transmission hump near the gear shift.

I'm not sure of the wiring but if the wire from the shift position on the ignition switch was routed through a NO switch at the shift which was closed when the shift was in Park or Neutral it would seem likely. If I try to start the engine on my pickup with the transmission in gear the ign switch turns to the start position but the starter doesn't run. If I hold the ign. sw. on and move the shift to Park the starter starts running.

Reply to
John B. Slocomb

Not a big deal to do , and I already have an aux breaker in place for the camping trailer . Not an optiopn though , this needs to be properly repaired - my wife drives it sometimes and she doesn't deal well with "modifications" .

Reply to
Terry Coombs

This one has the switch down on the column , actuated by a rod . Steve W. has suggested the switch , and since I gotta go there anyway ... and the rods are all covered by the shifter sleeve and a cover , can't see a thing without dropping the column . Already got the lock plate and turnsig module out , ready to remove the lock and pull the signal housing . But I'm checking the switch first , if it's bad I've already pulled more than I really needed to .

Reply to
Terry Coombs

Thanks John , but this one is all mechanical . I still remember the problems my daughter had with a '98 Firebird . Console shift , and sometimes you couldn't turn the key far enough to remove it . We finally traced it down to the cokes she'd spilled in the console , the sugar/syrup had gummed up the neutral release cable .

Reply to
Terry Coombs

You're probably right that it's a loose screw. If the switch moved and the rod is locked up on a ward, it won't move far enough. G'luck.

Reply to
Larry Jaques

Turned out to be the lock cylinder . Out of the column it wouldn't turn all the way - I could see where the tab had been hitting the stop .

Reply to
Terry Coombs

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