88 Blazer power lock problem-need help

[NoAngel]

I went to unlock the driver's side door with the key, no luck. I tried the passenger's side, no luck. I had to go in through the back window(which did roll down with the key). Once inside I tried to unlock the driver's side door with the power switch, nope. Then tried to pull the lock up manually, nothing. The passenger side door did unlock with the power switch from the inside. Any suggestions?

 

[azblazor]

Sounds like a problem common to both sides - bad or intermittent fuse, connector, return/ground connection. Do you have the factory wiring diagrams? They would be VERY helpful.

 

[Leadfoot]

I have the wiring diagram for her Blazer (so does she) as I had the hayes manual for my trucks, and the guy she bought the blazer from gave one to her. I put aftermarket keyless entry systems in my trucks from www.a1electric.com and have never had to trouble shoot them (and I think they are simpler than the factory style). I have a multimeter and test leads but am not sure what I am looking for. Is there a procedure for testing switches to see if there are bad contacts, etc?

 

[Hunden]

I have had the same problem with my 84 Silverado, it feels like the lock is getting ssuck on something, I just keeping turning the key back and fourth untill it eventually unlocks. I think it is a design flaw, because I have heard other people metion it also.
Damon

 

[dyeager535]

The key is totally mechanical, so if you can't open the door with it, there is something wrong with the lock mechanism, and unless the lock solenoid is somehow energized and holding it down (so you can't turn the key) your first priority should be to troubleshoot the mecahnical portion of the locks.

If it turns easily but doesn't do anything, the lock cylinder must have come disconnected from the lock mechanism inside the door. Not a hard system to work on, but the door panels have to come off.

 

[Leadfoot]

Dorian (or anyone),
If I unplug the connectors to the lock solenoid and try the key, it should take the "electronic" portion of the lock out of the equation right??? I figured I could eliminate the electric side and isolate the mechanical side. If that checks out fine then I would inspect the electronic components. Does that sound logical, or is the solenoid stuck in one direction when not energized (in essence trying to always force the lock one direction or the other)?

 

[dyeager535]

Yeah you could disonnect the solenoid wiring. Either up under the dash near the doors, or straight from the solenoid itself, but of course have to pull the door panels.

I'd really doubt the solenoid could stay energized long without other problems, I *think* the locks run through a breaker on the fuse panel, as well as a relay, so if they were stuck down energized, they would trip the breaker, and then no power would return until the breaker cooled off. At least ideally I guess.

Are you not able to turn the key at all or what? If the lock assembly is sticky, the solenoid won't push it up, they aren't very strong. The mechanical and electrical pieces of the lock are tied together, so if its stuck mechanically, it is electrically too, if that makes sense.

IIRC, both the solenoid, door lock knob, and lock cylinder are all hooked to the exact same piece on the lock assembly.

It's not the right thing to use, but I wd-40'd the whole lock assembly instead of removing it, hoping it would clear out some of the gunk and provide a little lube, and it worked.

I think I'll buy some of that grease that comes in a spray can that "solidifies", I figure that would work excellent in some of the places you can't reach easily.

Can't remember if the solenoids need to be grounded to the body or not to work correctly, so if you pull them, keep that in mind. With the door panel disconnected, I believe you can bolt them to the door skin for testing to make sure they are grounded well. You can pretty much pull on the plunger though to see if they are sticky or not...

 

[Rob 85K5]

put the key in the lock, push the button on the door handle turn the key to unlock. VOILA!! Happens to me a lot of the time. The worst is when it is raining and you are inside the truck when this happens. Then you have to roll the window down, push the button and then hit the pl switch.

 

[Leadfoot]

I'm beginning to think it is electrical, as you can unlock by hand, but as soon as you pull up on the lock knob and let go, it goes back down (as if the solenoid is staying energized in the down position). As soon as I get some time (funeral, races, working on my 78, work, my own side business, last truck pull of the season 9/29/02, etc.), I am going to pull the panels, remove the lock mechanisms (mechanicals), clean, inspect, lube. Then I am going to check the wiring and connection and use electronic cleaner (from work /forums/images/icons/grin.gif ) and dialectric compound on all the plugs and connections and see if that helps. I should be able to do this by 2003 /forums/images/icons/blush.gif /forums/images/icons/laugh.gif /forums/images/icons/tongue.gif

Michelle is really looking to learn how to do this stuff, so I think I will do the driver's side, while she does the passenger's side. I have a good general understanding, but still learning, so hopefully I won't pass on my mistakes to her /forums/images/icons/blush.gif /forums/images/icons/tongue.gif

 

[dyeager535]

I believe these get their power from the fuse panel, and its going to be one of the accessory ports up at the top. (the clip in one wire connectors)

I made my accessory port hookup since my truck didn't have PDL, but I think even stock they were wired that way. You may want to check that out. At worst pulling the plugs from the accessory panel, you will lose the power to the rear window. Plugging it back in will solve that /forums/images/icons/smile.gif

 

[BigBurban350]

On my Suburban, I have to press and release the door handle button on the outside, then it will unlock. It does that with all my doors. It also did it on my buddies old chevy.