Power Lock Troubleshooting

[C420sailor]

My ‘99 EB has weak power locks. Where the locks on my ‘98 are crisp and positive with even a quick press, you have to hold the lock/unlock button on the ‘99, and some locks won’t get full travel. Very flaccid, where the 98 locks are a positive KACHUNK.

The facts:

-Same results from all switches, door keypad, and factory remote
-I cleaned and ohm’d out the grounds at the battery. Clean and tight, 0 resistance.
-I cut out the splices to all the power lock wires in the harness under the rear left seat and resoldered them. This made the locks on my ‘98 way better. Little improvement.
-Hatch and glass locks are very intermittent and work less often than not.
-Fuse is good

I doubt all the actuators are equally shot, so it has to be something common here. A corroded common power or ground, etc.

Any thoughts?

 

[XLTrunner]

Here's an observation I made recently regarding the locks on my '98 that may or may not relate to your situation...but, it's food for thought. Anyway, I had an ongoing issue with my rear passenger side lock not extending fully from the day I bought the truck with 106K miles on it. If I needed to enter thru that door, I had to reach from the front door to lift up the knob. I just put up with it as that door was rarely used. Then, I started having issues with the driver side front door lock not extending or retracting fully. Now, I had reason to dig into this and eventually found that the driver door latch spring was broken and was wedged inside the latch; restricting the movement of the lock rod. I replaced the latch and voila...the lock snapped open and shut with more force than I ever remembered since I got the truck; along with the other locks. And, yes...even the lazy passenger side rear lock started functioning as well (fixed two problems at once!) I don't think this was a coincidence...and, can't help but wonder that the power needed to operate a weak lock actuator or gummed up latch doesn't somehow reduce the voltage directed to the other locks. But, I'm no electrical guru and have no basis to support this theory.

 

[C420sailor]

You could be on to something. I did find a broken spring in the bottom of the driver door the other day, and couldn’t figure out where it came from.

 

[XLTrunner]

Yep...that's the spring I'm talking about; except mine didn't make it down to the bottom of the door. There are threads on here discussing ways to replace that spring...but, I went with my opinion that a 20+ yr old latch was not worth repairing and I went with a new one so as to have one that operated without resistance due to corroded/tight pivot points.