Iterior lights

The interior lights in my '98 Venture van will not work, at all. Doesn't matter what I try. I've looked for blown fuses. I understand how all the switches work. The override switch in the overhead council. Also the dimmer/manual on switch located near the headlight switch. I can't even turn on the lights in the overhead council or the rear ones by pushing their buttons. No interior lights work. Oh, but the dash lights work fine as well as all the exterior ones. I've programmed the BCM to different modes and it has no affect. Anyone know of anything I could try before paying the man big bucks to diagnose? Is there a diagnostic procedure for the BCM? Any help is greatly appreciated.

The interior lights in my '98 Venture van will not work, at all. Doesn't matter what I try. I've looked for blown fuses. I understand how all the switches work. The override switch in the overhead council. Also the dimmer/manual on switch located near the headlight switch. I can't even turn on the lights in the overhead council or the rear ones by pushing their buttons. No interior lights work. Oh, but the dash lights work fine as well as all the exterior ones. I've programmed the BCM to different modes and it has no affect. Anyone know of anything I could try before paying the man big bucks to diagnose? Is there a diagnostic procedure for the BCM? Any help is greatly appreciated.
Have you checked for voltage (12 Volts) at the override switch? That's where I would start. Maybe that switch has gone bad.

Also, I believe that fuse # 35 (here (http://www.my-chevy-venture.com/fuses.html)) is the one that supplies power to the interior lights. Make sure you check it with a volt/ohm meter, or put a test light in both sides of the fuse socket. You should have 12 volts in one side at all times. Sometimes fuses look OK but are actually bad.

Let us know what you find.

Take Care,

Finally got back to the Venture this morning. Checked the fuse and it's ok and there is 12 volts at the fuse. Pulled the override switch and it looks like it's ok but... According to my manual there is a purple and dark blue wire going into and out of the switch. So I hooked the ohm meter at those to contacts on the switch thinking it would show and open and closed circuit when I switched the switch on and off. Well it didn't. There's also a gray and black wire going into the same plug as the purple and dark blue. It is the gray and black wire that shows on and off when the switch is turned on and off. Not sure if that means something is wrong or my manual is incorrect. Anyway, according to the manual the purple wire is the one that comes from the BCM. And I assume it should show 12 volts. Well it shows 7.5 volts. What do you think??

Thanks.

Finally got back to the Venture this morning. Checked the fuse and it's ok and there is 12 volts at the fuse. Pulled the override switch and it looks like it's ok but... According to my manual there is a purple and dark blue wire going into and out of the switch. So I hooked the ohm meter at those to contacts on the switch thinking it would show and open and closed circuit when I switched the switch on and off. Well it didn't. There's also a gray and black wire going into the same plug as the purple and dark blue. It is the gray and black wire that shows on and off when the switch is turned on and off. Not sure if that means something is wrong or my manual is incorrect. Anyway, according to the manual the purple wire is the one that comes from the BCM. And I assume it should show 12 volts. Well it shows 7.5 volts. What do you think??

Thanks.
I think you MAY have found the problem - it sounds like the switch is bad (Open).

Here is what I would do to confirm it. Do the following with the dimmer wheel turned (on the headlight controls) all the way ON.

Measure the voltage on the Dark Blue wire at the switch. It should have 12 volts on it. My manual says it should be Pin 5 of Connector # 1.

Flip the switch a few times ending in the ON position and measure the voltage at the purple wire. It should have 12 volts on it. My manual says it should be Pin 8 of Connector # 1.

If you don't have 12 volts on both sides of the switch (Dark Blue & Purple wires), then I would say the switch is bad. It could be confirmed by jumping the two wires. If the switch is bad, your interior lights should now be on.

A little info from my research:
The Dark Blue wire should have 12 volts on it, which comes from the BCM, through at least one other connector & cable. That could be called the "Input" side of the switch. The Purple wire connects to what could be called the "Output" side of the switch and would feed the 12 volts to the interior lights, if the right switches are turned on (dimmer wheel all the way ON).

One interesting note: While looking at the wiring diagrams, I noticed that there MAY be a 12 volt feed to an "Under-hood Lamp" in the same circuit that feeds the override switch. So - if you have this light under the hood, check to see if it works (I don't have one in my van). If it DOES work, the feed coming from the BCM should be OK.

I hope this helps. Let us know what you find.

Take Care,

I noticed my mistake later last night when taking another look at the manual. By then the computer was off and I was ready for bed. It was the dark blue wire that had 7.5 volts not the purple. I typed up my findings hours after working on the van and did it all out of memory. (Shouldn't do that at my age) So again I'm getting only 7.5 volts from the BCM. I did jumper the dark blue and purple wires but the lights still did not come on. After church I'm going to take more of the switch cluster apart and do some more digging. But I did confirm that the 2 prongs coming out of the switch that the purple and dark blue wires connect to, do nothing on the ohm meter when I switch the override switch on and off.

Thanks for your help, I will report back.

... So again I'm getting only 7.5 volts from the BCM.
Only 7.5 volts? Sounds like a loose or dirty connection to me (because you are getting "some" voltage).

Do you have that under hood light & did you check it? That is between the BCM and the override switch. You should also check the connector at the BCM and its wiring. It is the White connector on my BCM. I was down there recently when I did a BCM upgrade (http://www.my-chevy-venture.com/Upgrade-Body-Control-Module-BCM.html).

Take Care,

I went out and took a look at it again. This time I brought a few more tools and some jumpers with aligator clips so I don't have to hold stuff in my teeth when I run out of hands. Turns out the switch is ok. No I do not have the under hoad light option. Thanks for the link to your BCM upgrade. I was about to ask where the thing was located. It will probably be a few days but I'll get back once I check out the BCM wiring.

Thanks again.

Believe it or not I finally today got under the dash to take a look at my interior light problem. Pulled the glove box out and removed the BCM. I really thought the BCM would be the problem but after some circuit testing I think it may be a wiring problem. I'm getting 12 volts to the BCM. And the dark blue wire coming out of the BCM that leads to the interior light override switch has 12 volts when you open a door. When you close the door the power is cut like it should. But there isn't 12 volts at the other end of the dark blue wire at the over ride switch. I also jumpered 12 volts to the the switch's purple wire (bypassing the BCM) and the lights go on. Oh, and the switch works fine. My question to anyone that's fooled around with this, does that dark blue wire take a direct route from the switch to the BCM? Or does it make a stop somewhere else? When my wife gets the van back home later I'm going to run a wire from the dark blue off the BCM to the dark blue at the override switch to see if the BCM is truly ok. Any help is appreciated in advance.

dj1111 - This thread has been inactive for almost a year. In accordance with AF's guidelines, if you have an update or further questions, please start a new thread and link to the old one if relevant.Thread closed.