Wiring Harness Connector Location Map

[gw1500se]

I have a 2000 GMC Sierra 1500 4x4 (4.8L), purchased used, with some new odd problems. It started with the service engine light (see my orignal problem here). After receiving a new PWM solenoid but before I had a chance to install it, the odd behavior started. But first before this, was a problem with the power locks. I have an after market security system (Alarm Code) and occasionally when hitting a bump or coming to a stop the doors would unlock for no apparent reason. Sometimes the power lock switch (not the key fob) would not lock the passenger side and other times it would not work at all. I didn't pay much attention to it since it was no big deal. Not sure if that is related but the most recent issue is that when I start the truck and the service engine light is not on, the truck will not idle (stalls). After it warms up by keeping it above idle, I shut it off and it will start with the service engine light back on then run normal. I think there are 2 possibilities. Either the Alarm Code is messing up (if I knew how/where, I'd remove it) or there is a wire harness problem somewhere. It is my guess the problem is more likely to be the latter or at least that is where I want to start. After that long winded explanation my question is where can I find a map of connector locations so I can check them all out? A corroded connector is the most likely culprit. The wiring diagram does not say where the connectors physically are located. TIA.

[Jsdirt]

Aftermarket security system. Say no more. 99% of starting, stalling, or other odd electrical problems can be traced back to these units. Most are cheaply constructed, then to top that off, they're installed using the cheapest, crappiest electrical connectors on  the planet. Many a tech has a few stories about these.

 

In other words, that's the first place I'd be looking. Find the unit, and trace the wires out. You'll see where the factory wiring was cut, with the unit installed in series. Pull it all out, and toss it in the trash.

 

Which PWM (pulse-width modulated) solenoid did you buy? I can't think of anything that's PWM on that, aside from the alternator field, and a sensor or 2.

 

 

[gw1500se]

Interesting reply. Thanks. The solenoid was the one that is supposed to match the the tranny with 16 pan bolts (Standard Motor). It may be academic at this point as they may well not be the problem. Ive' looked for the system but without much luck. I guess I need to look a lot harder. I'm guessing it is attached under the dash and in such a way that there is no logo or identification plainly visible.

[Doug_Scott]

Trouble codes for some things are not set right away.  Some will wait until x number of faults.  Same for being cleared.  Some will clear the CEL after x number of restarts with the fault not present. 

From your description of how the door locks cycle after some jarring kind of bumps sounds like a poor/loose connection.  Chances are it will be one made by the installer of the alarm. Without knowing how the installer works, I would first look for the easiest access to the wires he had to connect to.  If you still have the install manual it would make it easier for you.  For example, if instructions say to connect purple wire to pwr door lock switch signal wire, the easiest place to do that would be in the door.  Take a look at the wire bundle that goes from body to the door and see if it appears to have been messed with.  By that I mean the ribbed rubber cover.  The example I gave is completely made up just to help explain what I meant.  Jsdirt is right though, find the controller and follow the wires to remove, or if you have instructions use them to assist in locating any of the connections and follow them back to locate controller. Good luck, I always dreaded trying to repair others accessories installs. 

 

Back when I was working at Plymouth/Chrysler dealership I got a warranty electrical problem on a Sapporo that the interior lights would come on as soon as the headlights were turned on and the dash lights were always on bright, they could not be dimmed.  I inherited the job from another mechanic who gave up after changing the dash light rheostat. Warranty paid straight time for wiring issues, that mechanic would refuse straight time flat rate, he could make more on customer pay jobs. I spent 4 hours on that car before I finally found the issue was caused by the shop that did the dealerships stereo upgrades and warranty work on sound system issues.  These guys figured all green wires are ground wires on Plymouth, so they connected to the first green wire they saw thinking it was a ground.  On Sapporos the green wire on the dash lights socket was for interior light and Max bright dash lights.  Those 4 hours included morning break and lunch, I figured straight time meant how long the car took up my work stall.  Guess they were lucky I got the job at 9am and not 4pm.

[gw1500se]

Thanks. The system was already installed when I bought the truck so no manuals were provided. It worked fine until recently so I have to assume it was wired correctly but now the unit is either failing or there is a corroded connector somewhere. Using the Alarm Code website it appears the unit is somewhere under the dash so I will need to find it and trace the wires. In any case it sounds like removing it is the best first option. The truck is old enough that I doubt there is any significant risk without it.

[gw1500se]

Good news and bad news. The good news was that removing the security system was relatively easy. The bad new is that it changed nothing. So I am back to my original question. There must be some corroded connections somewhere and I need some kind of map to find them. TIAA.