200ma Won’t Trigger Relay

hello, i looked at all 41 posts in the relay forum and couldn't find an answer, so here's my last resort before i give up. i just hooked up a dei automate 553 in my 89 saab 900. everything works except i can't figure out why the relay for the supervised dome lights won't work. when i touch the light tester to the BLACK/ white wire (done supervision negative output) i see that there is a negative output. when i connect it to the relay, it will not trigger. i have the relay set up as follows: 30 - negative dome light input switch 85 - BLACK/ white 200mA negative output from alarm 86 - 12V + 87 - Ground when i click on the alarm with the tester on pin 30 i get nothing, but there is still a very faint reading on 85 (but not near as dominant as the reading when on the BLACK/ white wire when not connected to the relay). by the way, i have tried three different relays. what is wrong here? Do i need to run a stronger 12v and or ground? thanks

Use a volt meter set to a DC voltage scale of at least 20 volts. Connect the red probe to terminal # 86 of the relay and the black probe to terminal # 85. Leave the relay wired as you have it and watch the meter reading when you activate the unlock feature of the alarm. If you don't get a reading around 12 volts, then place the red probe onto a know good source of 12 volts. like the main power input to the alarm. If you then get a reading after using the unlock feature of the alarm, you need to check the 12 volt supply to the relay for problems. If you still don't get a reading use a jumper wire to temporarily ground terminal # 85. The relay should activate. If it does, either there is a problem with the alarms output or maybe it needs to be programmed to activate.sparky

now that you mention it, i'm starting to question the 12v source. it's the power wire from the stock alarm that i removed. it's only 16 guage and i'm already running the alarm from it. tomorrow, i'll use a better power supply and better ground on the new alarm and the relay and give the reading a try... thanks... i appreciate it.

well it's not the power supplied to the relay. the relay is hooked up correctly and does trigger when i touch the 85 pin to ground. i went to borrow my dad's meter to test the outputs but he said it's broken. there is definately a negative feed on the BLACK/ white dome light supervision wire from the alarm because it causes my test light to light up when i press the remote unlock button. so now, i'm sure the problem is that the output from the alarm isn't strong enough to trigger the relay. what can i do to make that output stronger? thanks again

thank you very much.... i'll get out to radioshack tomorrow and let you know how it turned out... thanks again....

Have you checked your main ground for the alarm? There shouldn't be any reason the dome supervision wire doesn't trigger a relay. Thats what its meant for. It does draw its ground current from the main ground of your system. Where is this unit grounded? Try grounding it in the driver's kick panel. Make sure to scrape away paint first also. If you have a DMM, you can check the resistance of your ground source to the negative post of your battery. Thats where I would start.

i just regrounded it and no change... thanks