Door jamb switch

[Bonearzt]

Hi All! I've been a lurker for a while and have picked up a LOT of incredible info from you All, so THANK YOU!!

Had a weird situation pop up earlier today.
I'm replacing old wire for the dome light, 2 wire, no common ground, easy right?
But!
When I test the circuit , I get 0.32v with the jamb switch engaged, door open, under dash light on.
But when I depress the switch, dash light goes out and I get 12.96v in the dome light circuit!
Headlight dimmer switch has no effect, but itself might be faulty.....being old...
Thoughts?

Thanks!!

Eric

 

[Blue Ox]

Check the fuse for the lighter socket. For whatever reason, if that fuse blows the dome light gets energized.

 

[Bonearzt]

Interesting!

Thank you!

 

[H2OnSnow]

I get 0.32v with the jamb switch engaged, door open, under dash light on.
But when I depress the switch, dash light goes out and I get 12.96v in the dome light circuit!

Where are you measuring? From what to what? The courtesy light circuit is a low side switch arrangement. You always have batt at the socket and you switch in the ground connection to turn on those lights. The pin switches in the jambs and the headlight switch are making the ground connection.

12.9v might be low also. What do you measure directly on your battery?

 

[Bonearzt]

As I mentioned, 2 wires going to the fixture, no common ground.
I'm measuring between the two wires where I'm going to splice in new wire to the fixture.