Wiring Door lock relays

I am trying to wire up my compustar lcd type alarm to lock/unlock the doors of my 00 Jimmy.

The alarm output is (-). So i have used a relay for each lock/unlock to convert to a (+).

http://members.shaw.ca/donaldewasko/convert.jpg   (From Jeff @ Velocity)

I tried the neg input-->pos output diagram. The problem i get is 12v feeding back to the outs on the alarm. Now I'm thinking that it should be neg output-->pos out   not  neg input-->pos out?

How should i wire the relay to change the neg of the alarm leads to pos for the door lock/unlock wires. Would i need a diode to prevent the current going to the alarm or what did i wire wrong.

Thanks Donald

Negative input means input for the relay, but you use your negative output from the alarm. This diagram works.

I have tried this but get 12V on the wires that connect to the alarm and this will cause damage to the alarm. What can i do to stop this/is this normal. Is it possible that i have a wrong type of relay. They are the same shape with the same config of terminals as the diagram you provided but I don't know what to do to stop the current from travelling back to my alarm and ruining it.

Thanks for the post

Donald

How should the diode be installed. I don't really understand the instructional link on Diodes.

The side with the stripe should be where?

Thanks again

Don

That is because you do not need a diode.  Your diode is preventing positve flow toward the alarm right? This means that it allows negative flow toward the alarm though right? Which also means that it prevents negative flow from the alarm to the relay.  Which brings up the question I had earlier but never posted, why do you think your alarm will be ruined? They are outputs, and all you are doing is energizing a coil in the relay.  just hook it up and you will be fine.  Imagine if your car had negative door locks, you would just tap into those wires and those wires have 12v+ on them until you hit the switch and ground it.  Have you actually tried hooking up the relay diagram above or did you just think about it before you tried it and stopped?

J,

I did hook it up for approx 10 sec. there was some smoke and an awful burning smell. I opened up the CPU and on the board about where the lock/unlock leads enter in this order plug--small capacitor(?)--then a small rectangle shapped block about 2-3mm in size. It was this block that sort of melted. So I am assuming it was the 12v feeding back through the locks that did it :(

As an installer you come up to wiring keyless entry what needing (-) to (+) do you use two relays? No diodes? Cause i don't believe this should be so difficult. As I'm allmost in tears cause I cant figure this damn thing out.

In retrospect, I am ASSUMING it was the locks that caused the burning problem, because I have been over the wiring and all the other wires seem to be wired correctly and the main power leads are all fused so ?

-Don

Did it smoke just by hooking it up, or after you push the lock button did it start to smoke? In other words can you hook it up according to the relay diagram and just let it sit there and be fine? or does it smoke just by hooking it up?.  if you hooked it up according to the relay diagram, then your lock and unlock output is not doing anything until you push a button on your transmitter.