Yup. A new one on me.

94 S10

Been having the occasional problem with it not starting (turning over). Dash lights up, fuel pump comes on... but won't crank. I assumed either the ignition switch or a neutral safety switch was starting to go. You fiddle with the ignition/shift a bit and it would start.

Today (heavy rain?) it wouldn't start no matter what I tried. Until quite accidentally I found out that if the drivers door was open it would turn over and start just fine. Closed it and tried again... no go. Open, start.


There is an alarm, but it's been deactivated for a while (fuses removed), never been a problem before. I'm assuming it's a ground problem of some sort and the door switch is somehow getting involved in completing the circuit.

Sooo.... I'm not really expecting a definitive diagnosis, but I figured I'd better ask before I jump in, just in case this is a know quirk with a known fix.

 

A very common problem Ive seen working in the stereo/alarm shop years ago working with aftermarket alarm systems. Find the brain on the unit and cut the wire that feeds it the signal from the interior lights. Most of the alarm systems I have installed hook up to the interior lights to know if the door is opened (lights go on - starter is disabled). If the door is opened it turns on the int lights and engages the starter kill relay (which is always hot cause its got its power from the starter 12v hot at all times and not affected by removal of the alarm systems fuse). It will be quite easy to find the wire color online if you know what brand and model your alarm system is. It should be hardwired to the 12v hot at all times and the systems fuse will be bundled with the unit (prolly down by the gas pedal behind the kickpanel). You could also remove the starter kill relay if you like too. It doesnt have to be installed with the alarm system. Alarm systems are actually quite simple once you see the wiring diagram for it.

Howcome it was unhooked originally? Those brains for the cheaper alarms systems dont last forever.

 

But that's just the opposite of what's happening.




It was disabled before I got the car. They lost all the remotes.

 

Well if the guy 'unhooked' it himself then he could have not done it properly and the brain unit is still operational and fried.

You should just get in there and remove it totally. All the wires are just piggybacked into the cars harness, follow the wires and remove them. Have the battery unhooked when you do that. Then throw the alarm in the trash. Your starter kill relay will probably have yellow and red and orange wires coming out of it, and it will be inline between the ignition and starter, so thats the only one that will be tricky to unhook. When its removed you will have to connect the ignition back to the starter since that wire will have been but to add the relay into... The kill relay usually has wires that are only about 24 inches long, so it will be close to the starter somewhere.

Im by no means a professional at this stuff, but the ones I have had experience with are Alpine and Ungo brand systems that we sold where I was working at years ago.

try and find out what brand it is on the unit itself, and look up the installation instructions and read them from the back to front to uninstall it. Hope it helps you out.