Need help with Carling Switch for Cargo Light

[Jakea333]

Originally Posted by Deep Water Dan

Sure it will. I told him to run the wire to the cargo lamp side of the relay where it will power the cargo light directly with the 12 volts from the switch. He won't be activating the cargo light relay, just bypassing it. But the relay will still be functional when a door is opened.

Doh! I misread what you said. That would work just fine.

[inov8]

Since Jakea333 was so kind as to look up the wire colors, I've added them to the drawing.

Terminal 7 of the switch can be connected to either Pink or Black vehicle wire. Pink will allow the lower switch lamp to dim with the instrument panel bringtness control, whereas Black will not (always the same brightness).



If the lower switch lamp is an incandescent bulb, then terminal 6 and 7 polarity does not mattter. If it is an LED, then polarity does matter; the LED will only light when polarity is correct.

As Jakea333 also pointed out, the diode part number is not critical. Virtually any diode will work fine, as long as reverse breakdown voltage is at least 50 Volts.

[Deep Water Dan]

inov8's plan is good also. Both would require about the same amount of additional wiring. The only potential problem with using a diode is that should it fail, you'll probably end up buying a new BCM.

[dr09fronty]

You guys are AWESOME!! First chance I get I'm going to try Deep Water Dan's recommendation and then post an update. They are all BRILLIANT solutions and I am thankful.

David

[inov8]

Here's one possible schematic for Deep Water Dan's idea. Seems a perfectly good approach to me. The switch simply bypasses the cargo lamp relay contacts. It should be able to handle the bulb inrush current OK.

[dr09fronty]

inov8 - the schematic is STELLAR! Thank you, thank you, thank you...

[dr09fronty]

It worked, kind of. I used a wire tap on the lamp side of the relay (green wire) and connected the other end of the wire (red) to pin 3. I then ran 12v from the power outlet near the glove box to pin 2 and used the ground from the same power outlet and ran it to pin 8. I inserted an inline 10 amp fuse between the switch and power outlet. So everything is wired somewhat like the schematic that inov8 developed, except I kept the stock black wire on pin 7 (ground) and violet on pin 6 since these we working before.

Now keep in mind I was doing all the wiring while I had the relay removed. Time to test. I turned the switch on and Bingo! The top bulb of the switch illuminated as well as the cargo light. Tested with parking lights on and bottom bulb of switch illuminated – great! Turned switch on – great – everything working! I’m happy, time to celebrate!

But wait, I have to plug the relay in. So I plug the relay in and the top switch light illuminates (even though switch is in the off position) and so does the cargo light. WTF?? I close all the doors, no difference. So something is activating the relay. I checked a few things but due to other commitments I had to call it quits.

I’m pleased that the switch is working as designed but that darn relay keeps getting in the way. For now I’ll run it without the relay until I have time to give it more thought. If you guys have any ideas for the wiring configuration I’m using please let me know.

Thanks,
David

[Jakea333]

It sounds to me like it is working correctly. The idea was to leave the relay's functionality in tact, so that the cargo light works as normal for the most part. This means anytime the doors are open the light will be on, and once they are closed you must wait for the light to go off (it has an internal timer of something like a minute). Did you wait at least that long for it to shut off? Off-hand I don't see anything that would cause it to stay on permanently.

Anytime the lamp is lit, the upper bulb will be lit. This means the top light in the switch will light up even if the switch is not in the "on" position.

[dr09fronty]

Jakea333 - you are correct (how embarrassing, I should have known that). Every thing is functioning correctly just as everyone said it would.

A big THANK YOU to all who responded to this post and helped me, I appreciate your knowledge and time. It was a good learning experience for me.

David

[Jakea333]

Glad it all worked out!

Care to post a pic of it in its finished state? I'm tempted to do this myself, now.