Door switches

[Bernie]

Okay, I'm installing a new alarm in my 99 GMC C3500 C&C dually and I'd planned to use the existing door pin switches for the alarm triggers since these trucks are a PITA to add pin switches to. Even GMC didn't try putting them in the frame, instead they mount on the ends of the dashboard.

So, I have what I thought was the full set of wiring diagrams for the truck, except they don't show that little detail. They do show the interior illumination control module, but not what wires hook up to it, or what they're for.

I'd rather not have to rip the dash apart to see what wires (colors) are on the switches, and you can't get to them from underneath due to the parking brake on one side and the HVAC on the other side. And I can't just hook up to the dome light because the interior illumination module controls that with a delay after you close the door, and an override button (that I use) on the dash to keep the dome light off when the door is open.

Anyone know either what the wire colors are on the switches (and if they switch ground or hot), or an easy way to get the switches out so I can see the wires myself?

 

[Zembonez]

Unfortunately I have no clue. Scotty might if we can rouse him. He has done a bazillion alarms in these.

BUMP

 

[700 sportsman]

You should be able to pop the switch out of the dash. Or if you can't get it out (I think I've had mine out before though) you should be able to take the buzzer module that is under the dash and look what color the wires that feed the top left pin are, I nipped that pin off the module to eliminate the door buzzer.

If you can't figure it out, I'll take a peek in my service manuals, I remember it was a PITA to find, but it's in there somewhere

 

[Bernie]

Found alarm hookup instructions online for a 1998 that should work nicely.

http://www.commandocaralarms.com/wiringdetailsprint.asp?id=597

 

[700 sportsman]

Yep, from what I found in the service manual it is a purple wire, and a black wire at the both the LH and RH door jamb switches

 

[Bernie]

Yep, from what I found in the service manual it is a purple wire, and a black wire at the both the LH and RH door jamb switches

I'm betting the black goes to ground and the purple to one side of the switch to disable the dome light that's located at the headlight switch. If I tap into the purple at the headlight switch that should give me a negative trigger for the alarm if either door is opened, even if the switch is set to disable the dome light.

Now all I need to do is add pin switches to the rear doors, hood and the side boxes and I'll have all openings covered.

I don't really care about the starter disable since I'm more concerned about the truck being broken into than I am about it being stolen.

 

[Bernie]

Oh, and I still need to mount the shock sensor in the back compartment and the siren in the lightbar.

 

[700 sportsman]

Do you have pin switches? or where do you plan to got those?

 

[Bernie]

Do you have pin switches? or where do you plan to got those?

Magnetic reed switches. I have a bunch of 'em from installing home security systems.

 

[ScottyBoy]

There is a wirre at the headlight switch that is negative when a door is opened, regardless of the domelight position on or off. I'm not 100% sure on the color, but I think its purple, or maybe purple with a white stripe. If you have a meter, test all the wires and you should find the correct one. Also, the doorswitch pins can pop out of the dash if you slowly wiggle them out with a screwdriver or a pry tool. They just pop into the sides of the dash. Or you can reach your hand up under the dash and feel for it and push it out. I've done a ton of those. Also, those pinswitches are notorious for going bad/jamming up.