This 1995 Chevrolet S10 pickup came in with the complaint that the park lights would work until the brakes were applied or the turn signals were switched on. In reality none of the rear lights were working as they should. It all sounded like a bad ground to me so I wanted to start by checking the ground at one of the bulbs. There are two phillips headed screws that hold the light assembly in place. Once removed the assembly will pull out.
The socket twists to unlock and then pulls out of the lamp assembly. Note the bulb elements in the following picture. Although only the park/tail lights are turned on both elements are glowing and neither one is bright. This is due to a poor ground condition.
To further prove the faulty ground condition I back probed the black ground wire where it enters the socket assembly. Note that my test light is illuminated in the next picture. This is due to un grounded power back feeding the ground wire.
This was a pretty easy diagnosis when I spotted the cut ground wire under the driver’s side rear of the truck.
The factory ground bolt was heavily rusted and would not come loose without a lot of effort. It is just barely visible at the center of the next picture.
Instead I drilled a new hole in the frame.
I lengthened the damaged wire and added a ring terminal. I secured it to the frame rail with a self tapping screw. It does not look like it but I did wire brush down to clean metal. Afterwards I sprayed some black paint on the connection point.
Now the stoplight element is bright when the brakes are applied.
This customer is going to have a lot more problems with this truck due to heavy rust on the underbody.
I replaced the battery yesterday and the engine check light disappeared throughout the day. It’s on when the switch is on before start, but as soon as I start the engine it disappears. Today in the morning the problem is back again and the car shuts off. After I rocked the car it started okay, I understand that this code is related to bad PCM but why it happened only in the morning, and why it works fine after rocking?
I didn’t disconnect the battery,the only code they could get was P0601. I checked the battery voltage before I start the car it reads 12.5. I used a jumper wire instead of the ignition relay and the car cranked without starting. Again I have to rock the car really hard to get it run for the rest of the day.
A code P0601 is almost always a PCM replacement. The few exceptions are a faulty battery and severe misfires. I would strongly recommend having the battery load tested. If the battery is okay and all connections are clean and tight, replace the PCM. It has to be programmed to work.
I do need some information to help you. Was the battery disconnected while the vehicle sat for three months? Have the engine and ABS(if possible) codes read and reply back with the code numbers.
Hi Sparky, I really need your help!
I have some weird issue if you can give me any suggestion or solution please. I have trailblazer 2006 ls ext, it’s very well kept and I do maintenance regularly. I parked the car for 3 months and it was fine then, when I came back I tried to start the car it started OK, then engine turned off, then cranked a little bit it started with “engine check ” light. It worked OK but each day in the morning, when I start the car “engine check is on” but the car starts OK then after 1 -2 minutes lights of Traction control and reduced power come on and the engine dies. I try to start again but it won’t crank and all 3 lights are one after waiting for 5 minutes it starts OK and it works fine for the rest of the day with engine check light on. Every morning I have the same story, I noticed one thing I don’t know if it’s related, after the engine die if I rock “shake ” the car I can start it immediately without waiting. I sent the car to dealer and it seems they don’t know what is wrong, they suggesting to replace all the electrical wiring and loom in the car !!! for 2700 USD!!