I just blew a relay in a keyless entry system I installed when I used the factory power door lock buttons on the door. What did I do wrong? The voltage clearly went back up into the keyless system when I used the original door locks. Luckily it was not a system I am using in the finished car, it was cheap $15 Amazon system. But any idea how I can prevent this from happening? The wiring is hard to see so I will try to go get some photos a little later.

Thank in advance for any help.

I assume I need to get some relays and have them trigger the door locks correct?

You need relays!

Very few systems have on board door lock relays, and those cheapy ones for sure don't. The positive triggers on most alarms without onboard relays are only able to output 1/2 a milliwatt so no where near enough to move the door locks.

Wire it like this picture:

http://www.the12volt.com/relays/relaydiagram1.html

The Fiero uses a positive trigger door lock relay. This means power is applied to the relay coil via the lock/unlock switch and the coil grounds through the metal housing. Most aftermarket systems are a negative trigger. If your system is a negative trigger you will need to use a pair of relays to activate the factory power lock relay.

Does it tell you in the instructions if your keyless entry system is positive or negative trigger?

Basically, you need to set up your module to feed 12v+ to terminals "A" and "B" at the lock relay.

Here is the FSM wiring diagram:

[This message has been edited by seajai (edited 06-10-2017).]

My keyless system can be both positive or negative trigger.

Thanks everyone! I have ordered relays with harnesses. I am so happy I blew this keyless system up instead of my other system. I am in the middle of replacing this system to go to one that has the key fob built into the key head and I have been going to a ton of work to make it right.

I learned a lesson today and luckily it was a small price. I cannot tell you how panicked I was when I smelled the burning electronics but could not locate the source. I have ordered a battery disconnect so in the future if I have an electrical problem I can quickly kill the power.

Shoot it's only been a couple months since I put mine in and I completely forgot about the OE relay in there. So now I remember all I did was connect the + door lock and + door unlock to the activation wire of the stock relay. I didn't add any extras as in the link I posted above.

Per the 87 diagram at the stock relay I tapped into the Lt Blue for + Lock and Black for + Unlock.