I have 1 1998 F150 and the dome light does not come on when the doors are open. The door switches seem to be working since the door ajar light comes on when the engine is running and a door is opened. The dome light comes on with the control on the dash so I know the bulb and wiring to the dome light are okay.
I would not be too concerned about this except I am installing a security system (aftermarket) and it needs a door open trigger to work. In the past (on other vehicles) I have used the dome light circuit as the trigger. Does any one know which wires (color) run to the door switches and whether they provide a voltage or run voltage to ground when a door is opened? I was thinking of using these wires to provide the trigger.

Thanks,

Bruce

 

Does it ding when your door is open and keys still in ignition? That lets you know the door triggers are working. This is an easy install. Your door triggers should be working if the door ajar light is coming on. Let me know if this helps.

D Beames


|....... ITEM..........|...WIRE COLOR .......|POL|...WIRE LOCATION
|..DOOR TRIGGER|.blk/yel & blk/pnk....|- |......*5 |

Notes:
*5 The black/yellow catches the drivers door and the black/pink catches the passengers door. Use both wires and diode isolate each. See direct fax document #1076 for wiring information. The wires are found in there respective door harnesses. Both wires may also be found at the GEM module located above the fuse box. On models without a dome light delay use orange/lt. green (-) at the light switch.

 

D Beames,

Great information. Thank you for the very quick reply. I will give this a try today.

Bruce

 

D Beames,

One question I forgot to ask is how do I find the direct fax document that you referred to?

Thanks,

Bruce

 

The Direct Fax is a documentation that is available through the software that gives out the wiring diagrams. I don't have my program anymore, so I don't know how to get ahold of the fax. It isn't necessary for install. Just remember that the door triggers are - pol. and they are in the kick panel harnesses. If you have any questions, ask. I put my alarm on my 98 F150. Easy as pie. I am also a certified installer for mobile electronics (audio/video/security).

D Beames

 

D Beames,

I found the door switch wires that you referred to. They each show a positive 12 volts with the doors closed and 0 volts with the doors open. What is the purpose of the diode isolators? I ran a new wire from each of the door switch wires and connected the new wires together to the alarm trigger wire. When either door is opened the voltage goes to 0 and triggers the alarm. The door ajar light comes on when the ignition key is turned on and a door is opened and the chime sounds.

Thanks again for the great help.

Bruce

 

The purpose of the diode is to keep the voltage isolated to the specific door. Example: If you wire them both together (splice) then to the alarm trigger, it will cause the signal to travel reversely to the computer of the truck. In other words, when you open the passenger door with the keys in the ignition, it will chime like you opened the driver door. You don't want that. You have to keep the signal from travelling back to the passenger door. Isolate it like this:

Get TWO 1 ampere diodes. Diodes have a ring on one side, left or right of center. That signifies which side is the anode side and which side is the cathode side. The side with the ring around it is the cathode side. You want to connect the door trigger wire to this side. Repeat this for the other wire, same way. The anode side (side without the ring), you will connect these together and then to the negative (-) alarm trigger input. That should fix you up. If you need a picture, let me know. Its easy though.

D Beames