Hello,
I have a 1993 Blazer, 4dr,4.3 TBI, 2wd manual, PW, PL.

I bought it because I only like to drive stick shifts, and this was the first s-series blazer I had ever seen with a manual tranny. Maybe they aren't rare elsewhere, but 'round here they are hard to come by.

So, my power locks don't work. I perused around this forum and found some info, and now would like some additional advice.

Nothing happens when I press the lock/unlock button on either door switch.

I have power at all of my fuses (on both sides as appropriate). I believe the Power Lock fuse is one of those large metal ones (like the power window fuse). IF that is the case, I have power on both sides of it, however, the metal casing is gone and it appears to have overheated at some point. (plastic around it shows signs of high heat).

I found the relay attached to the bracket holding the gas pedal. Looks normal, but I don't know how to test a relay. Looked up the relay on Autozone.com and they want $22 for it and it is not stocked locally. Kind of a lot to spend on a guess.

Normally I'd go to the parts yard and grab some spares and try it that way, but you pretty much can't find a Chevrolet in a junk yard around here. And if there is one, you better be there fast,cuz it gets picked at quick.

I have a multimeter, and understand how it basically works. But I don't really understand relays so I don't know what to test for where. For instance, where does the power enter the Power Lock system. How is that power communicated to the switches and actuators?

Any suggestions are greatly appreciated. thanks in advance, ray

 

first thing i would check is the ground wire in the system and if your getting power at the switch. you may have a bad ground...in that case you could add a ground to the harness off of the ground wire thats built in and there ya go. as far as the relay check around the other power boxes for the same relay and swap them out, thats how i find out if its bad or not.

hope that helps ya.

 

The power lock relay is unlike all of the other relays. I did find one at the junkyard yesterday, and briefly slapped it in to no avail.

As far as I can tell, I do not have power at the wire harness leading to the switch.

From what I can tell, the fuse melted into the fuse box and was damaged in such a way that it appeared to have power on both contacts but it was not actually delivering power thru to the other side.
In other words, the fuse had power, but not the wire leading away from the fuse.

What I would like to do is remove the two wires (labelled Pwr Acc) from the back of the fuse block and wire in a new 30 amp fuse and see what happens next. (with the hope that the power locks or the power seat will start working....)

To do this, I would like to pull the fuse block out, away from the floor/firewall. It appears to have screws holding it down. Anyone ever removed one? A 1/4 inch drive will not fit into the hole to remove the screw, even a deep well isn't long enough.

Failing any help here, I will return to the junkyard. they got a 91 model a couple days ago that matches mine and I can rip theirs out without worry of damaging anything and then see what I have to do.

 

Okay, so I pulled the fuse block out of a similar (1991 4 door) blazer. I could tell that it was a little different from mine, but figured it was still worth a look.

A power wire comes into the back of the fuse block that powers both the stop light and the "Pwr Acc" slots (via a common terminal).

The opposite side of the fuse for "Pwr Acc" is another common terminal which has four connections accessible from the front side of the fuse block. There were no wires coming off the back of these terminals on the junkyard fuse block.

On the junkyard fuse block, there were wires plugged into these slots on the front, I assume to power various accessories.

On My fuse block there was only a wire in one of these front slots (orange with a black stripe). I plugged it into another power source on the fuse panel and lo and behold my power driver's seat started working.

Still nothing on the power locks, though.

My relay has six wires: small black, tan, orange with a black stripe, large black, gray, and blue. (this orange with a black stripe is a smaller wire than the one powering the power seat)

The gray and tan ones go to the actuators.
The blue, orange w/ black stripe, and small black wires go to the switches.

Still don't understand how the system works, where the power originates and how it flows through the system. Currently seeking a wiring diagram.


On a separate note, there was only one other wire plugged into the front of the fuse panel. It was a small orange wire plugged into a slot marked "bat". I pulled this wire off and plugged in the power seat wire (before I knew it was the power seat wire). When this small orange wire was unplugged, I still got a voltage reading of 1.6 volts from it. I didnt plug it back in, since it seemed wrong to plug in a wire supplying 1.6 volts to a receptacle supplying 12volts. Possible short, I suppose. I havn't checked to see if anything has stopped working and I do not know what this plain orange wire goes to yet.

 

I obtained a wiring diagram from Autozone's website.
I first checked the ground; it was good.
The wiring diagram informed me that the orange with a black stripe wire was the power wire for the power lock system. I could not see where this wire went into the fuse block.
Using my meter I checked for continuity between the power lock relay and various terminals on the fuse block until I found the terminal(s) that were in the same circuit.
I then jumped power to that terminal and pressed the power lock button on the passenger door (drivers door is currently disassembled). I heard a clicking from the dash, but nothing happened.

So I replaced the power lock relay with the junkyard relay and jumped the power again. This time the locks worked!

However, I had no continuity between the power lock relay and the drivers door switch. I pulled back the rubber wire cover in the doorway and the orange with a black stripe wire was broken in two. A quick splice should fix that problem.

So I am going to fabricate a small wiring harness that will run from an open 12V source through a 30 amp circuit breaker and then to the power lock terminal on the fuse block.
I am also going to run a separate circuit breaker for power drivers seat.

I havn't found out what the orange wire that had 1.6 volts does yet. I am going to leave it unplugged until I figure out what isn't working, and then try to diagnose that.