Adding Alarm w/door locks, 88 Scorpio

I've installed a security system on my '88 Scorpio.  The alarm works just fine.  The problem is with the door locks.  The (-) 500ma (Blue/Green) wires do not activate the lock/unlock.  I've searched the forum and have found this:  "Door Locks Require A Hard Chassis Ground To Operate, Must Use Relays; See Note #201 - Negative Pulse Door Lock Diagram."  I'm looking for the referenced diagram.  I did find the "3 Wire Positive Door Lock" information.  I see the 30 - is wired to positive door lock/unlock wire but the Merkur is a negative wire (Yellow Lock / White Unlock) is this where the wire should be connected?  Should 87 be ground?  What about 85 and 86 that show connected to fused 12v+, should that be ground or remain 12v+?

Thanks for your help.

Newbie to forum!

Thomas

You need to add relays to increase the grounding current. Use a DEI 451M module, about $10 on ebay or a pair of relays, wire thus. Use 4 or 5 pin, it doesn't matter which:- Alarm lock green to 85 lock relay. 2 amp fused constant to 86 both relays. Good chassis ground to 87 both relays. Alarm unlock blue to 85 on unlock relay. Lock 30 to yellow. Unlock 30 to white. Diode each relay, across the coil, 86 and 85, 1N4004, band to 86.

Thanks Howie! I'm going to go with the DEI 451M module. How will I wire it to work in my Merkur? Thanks.Thomas

Follow the instructions for type B but here they are any way. Green on alarm to thin green on 451. Blue on alarm to thin blue on 451. 451 thin red to 12V+ constant, fused 2 amps. Violet (purple) and violet black to a good ground. BROWN / black and WHITE/ black tape over, not used. GREEN/ black to yellow on car. Blue/black to white on car.

Howie, I received my 451 today and wired it exactly as you instructed. Still not working. The 500ma from the alarm doesn't even trip the relay. I set the alarm to hold the pulse for 3 seconds but I only get about .5V on my multimeter. I know the relay is good because when I ground the thin green or thin blue wire, the lock works. Am I missing something or do I need a different relay. Could it be the alarm? This is the second one I've tried with the same result. ThanksThomas

With the 451 in place take the thin green to ground that should lock then do the same with the thin blue, that should unlock. I think your first attempt, direct wiring would likely have blown the internal lock/unlock circuitry of your alarm.

The thin blue/green wires unlocked and locked the doors. I do hear the alarm module "click" when I hit the lock/unlock button on the remote. Do you think I've blown the internal lock/unlock circuitry? Is there any way to test it? Thanks again for your help.Thomas

Yes see the original lock and unlock wires go to ground on arm and disarm.