73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Interior & Equipment => Topic started by: Smitty31 on October 07, 2017, 03:22:03 pm
-
1986 custom deluxe, I have a courtesy ( no dome) light under the dash. It has always worked when you rotate the headlight switch to the left. But has never worked by the door jamb switch. IT only has one located on the drivers side of the truck. The passenger side has a plastic plug in it. So today i bought a switch took the other one out and the wire fell off. So I located where it went through a rubber grommet and the wire fed into the jamb. I pulled it out a very light tan wire almost pink looking. One single wire I checked it for voltage and there was none. I checked every fuse and all fuses was good. there is only one wire so i assume the switch grounds on the door jamb. Why is there no voltage on the wire. So very confused your help will greatly be appreciated.
-
The tan wire is for the key warning buzzer - it has voltage only when the ignition is switched on. The courtesy lamp is not presently wired into the door jam switch. You will need to add an 18-gauge white wire between the existing white wire to the courtesy lamp and the "unused" terminal of the door jam switch.
-
so why was there a door jamb switch on the drivers side. Was it for that buzzer and it connects to the switch? if so connect it and run a white wire over and connect to the other spade and switch will ground itself i suppose. just trying to think out loud and figure this out thanks your input is greatly appreciated.
-
im a little confused the white wire that goes to the courtesy light only has power if i rotate the the light switch to the left. So how will that make a difference?
-
Each door jamb switch is DPST shunted to ground. The key warning alarm connects to one pole of the driver side (left) door jamb switch as a standard feature, so that the key warning alarm will function. The courtesy/dome lamp connects to the remaining pole of the left door switch, and to one pole of the right door switch, whenever cab entry illumination is purchased as an option. Hence, in the standard configuration, only the left door switch is installed from the factory. The two poles of a door jamb switch are electrically isolated from one another while the switch is open (door closed). Both poles complete to ground when the switch closes (door opens).
The way your vehicle presently is configured, only the key warning alarm connects to the left door switch. The unused pole of the switch is "available" to connect the courtesy/dome lamps.
When cab entry illumination is installed, the two door jamb switches are electrically wired in parallel with the courtesy/dome lamp switch that is integral to the headlamp switch. This way the courtesy/dome lamps illuminate no matter which door is opened or when the dash lamp rheostat is rotated fully CCW.
Cab entry illumination is wired opposite to most other electrical appliances. They operate by switching the ground path instead of the power supply. That is, the courtesy/dome lamps receive constant battery power - power to the courtesy/dome lamps is not switched ON/OFF. They illuminate only when their circuits are completed to ground through the door jamb switches or the dome override of the headlamp switch. The "white" circuit coming from the courtesy/dome lamps are electrically "live" until either the headlamp switch knob is rotated fully CCW to detent or, when cab entry illumination is installed, until either door is opened, at which time the white circuit is grounded and drops to zero.
-
Man thats awesome thanks so much for the advice.
-
Thank you so much I now have a courtesy light and dome light (just installed dome light truck did not come with one) that works off the door jamb switch. Also you will notice in the pic my brand new headliner. Truck did not come with it either.
-
You're welcome. Just add the right door switch and you can enjoy the full upgrade. It looks awesome!
-
door switch is already installed on drivers side and working great. ive still got the passenger side to go.