Bob2.0

I don't know if I've broken etiquette here by starting this thread after posting a similar one, but I thought some rewording was in order.
Mission Objective: Short of taking this car to a specialist, I'd like advice on how to proceed in fixing an electrical problem I have.
The Challenge: When turning on my headlights, my climate control goes dark and becomes unresponsive any adjustments. To change anything, I have to turn off my lights first. I noticed this after my after-market stereo was installed by a recently deceased friend. Because of another repair I had to do, the dash and bolsters are removed, exposing the wiring. I see that the connectors to the OEM radio are just hanging there in the dash. The connector to the new stereo has wires going out of it to the four new speakers, plus three black wires, and a blue, red, yellow wire. (an orange one is not connected). These become a collection of wires that go between the seats, behind the passenger seat, and into the storage compartment where they are then wired into what appears to be the old radio receiver connector.
Your Mission, should you choose to accept it: I need a game plan here... what would you do to solve this mystery if it were your car?

Kevova

You should check for lighting codes. Problem most likely related to radio install. I would disconnect radio power and ground wires and see what happens. I would get FSMs.

Bob2.0

Thanks for the reply Kevova. I have the FSMs but didn't think they'd be helpful in diagnosing something that was caused by an aftermarket alteration HOWEVER, I just went out during my lunch and completely disconnected the harness from the stereo, and disconnected the harness where it was wired in to the old stereo connection. When I turned on the headlights, the climate control still went dark, so maybe the stereo installation was coincidental.

Frustrating, but closing in...

desertmike1

This sounds like an ground issue; turn one system on, and another goes out!

I would "research" and check my [Grounding] needed for the HVAC Controller..

antfarmer2

look under the carpet on the driver side just infront of the door.

Bob2.0

I removed the carpet and both of the ground wires appear to be fine. I turned on the lights and watched the display on the climate control to see if they'd flicker as I moved the wires around, but nothing changed. I will unbolt them and clean them really good tomorrow and give it a closer inspection. I'll let you know what happens.

antfarmer2

disconnect the battery first better safe than sorry.
look at the grounds for your headlights under the hood too just shotguning now.

Bob2.0

Well, it's about time I learned more about the electrical system on this car... looks like this is my big chance.

desertmike1

You need to remove the grounds in order to inspect them properly, sometimes corrosion hides under the connections..

Another good test while checking a ground; set up a DVOM on the 12volt Scale, place the red probe at the ground being tested, and the black probe on your "Battery Grd", a long piece of good Quality wire may be necessary in order to reach the Battery!

Now; when you energize a Circuit that utilizes the "Grounding point" being test, Observe the Voltage reading: a 0 volt reading would indicate a perfect Ground. a 12 volt reading would indicate a terrible Grd. This particular test will check the circuit, whiles it's being "loaded"

here's a video to give you an idea..

Bob2.0

I don't have a multimeter but that sounds like a tool I should have in my garage. Thanks for the advice and the video!

LouisvilleLT4

It really is. i diagnosed a similar problem where current was running backwards through my interior lights circuit using the ammeter part of mine. Turned out i had screwed a center console screw through an orange power wire to the lights, grounding it and causing current to flow through the lights backwards when they were supposed to be off.

Bob2.0

Thanks for all of this input! We'll get this thing figured out yet.
I ran out at lunch, disconnected the battery and then removed, inspected and wire-brushed the ground wires in front of the drivers side door. Still no change. I'll check that ground with the multimeter, but as this is new "ground" for me, I'm still not 100% sure on where to go from there so don't get too far away from your computers over the next few days...

antfarmer2

check the harbor frieght flyers the give the meters away all the time

Bob2.0

Coincidentally I stopped by Harbor Freight on the way home from work and bought one along with some zip ties.
I tested the ground by the door with it and it came up all zeroes, so we have a good ground there. Time to learn how to work this thing.

Bob2.0

As I'm having to work late most nights, Saturday will be my big day for finding that ground problem. I am watching videos on how to use the multimeter and it's all starting to make sense, however, I've noticed that there is some conflicting information on how to test for a ground. Some videos say to use the DC volts setting and some say to use the ohms setting ( ). I ran out this morning to check this and when I did this the DCV setting showed 0.00, but the ohms setting I got a .14 reading. When I got to work I checked it again and this time it fluctuated between .03 to .01. I will borrow the Museum multimeter just to make sure there isn't a problem with my unit, but I'd like your feedback on this.

antfarmer2

wait a min you work at the museum??????

Bob2.0

Yes. Scroll down to Bob Bubnis. That's me.

http://www.corvettemuseum.org/learn/...useum/contact/

desertmike1

???????

Anyhow, you have been busy researching meter's.. good for you!

You can test a grounding circuit with a meter set up for DC/volts or ohm's scale either will work just fine, with the exception that when you test a circuit with the ohm's scale, you are "Not" loading the circuit.

antfarmer2

nice to put a face to you! I would think you could get better info there.

crowz

What year is the car? I tried to find it in the thread but didn't see it listed.