'98 Regal starts by itself

04-21-2013, 11:44 PM
A friend's '98 Regal LS started acting odd the other night. He was on his way home and all the dash gauges and lights went out, then came back on and flickered here and there the rest of the trip. Here's the rundown: In the accessory position, radio works, things seem to be fine. In the run position, the car will actually start by itself, but gauges only come to life for a second or two, then the car will turn over for 3 seconds or so, and even if it starts right up, the starter runs on for a second or two. Per research, and personal knowledge base, I told him most likely problem was ignition switch. So he switched it out, exact same problems. So I told him to re-hook his original ignition switch back into the harness and turn it with a screw driver, so he was going to do. However, he didn't even have to turn it, just sitting there holding the switch end of the old switch, the dash lights would flicker, the fuel pump would prime, etc. So, now I'm wondering if it's his BCM or it it's possible that some interface in the gauge cluster could cause this. Anyone have any ideas?

Tech II
04-22-2013, 10:51 AM
There is no way the vehicle should crank with the key in the "on" position......only way that happens, if you have a bad ignition switch, or if you have some sort of alarm/remote start in the vehicle, and the module to it or wiring is some how back feeding....

You may have bought this vehicle and don't even know it has an aftermarket module......try dropping the hush panel on the driver's side, and see if a module and harness is attached(usually with quick connectors), to the original wiring....if it is, must be completely removed and wiring repaired....

04-22-2013, 11:44 AM
I didn't believe it either, but he came to my house and showed me, then we removed the ignition switch from the column, and turned it to the 'run' position with a screwdriver, and it started right up. I was on my way out, but told him to look for a module that was wired in after the fact and if so, to remove it. He looked on the driver's side underdash, and nothing, but today he was driving it to work and heard a click or two and the dash came back on. Said the clicking was on the passenger side dash, so he's going to check that side tonight.

04-23-2013, 01:38 PM
Mini Update:

After thorough under dash inspection, no aftermarket modules found. Dash/Gauges/Radio only worked correctly for awhile yesterday, then back off. He pulled crank relay, everything was dead, also unhooked cluster wiring from cluster, no change, still started in run position.

Tech II
04-23-2013, 05:51 PM
OK, so you are saying, he turns key to "on", the car cranks and starts, and the starter disengages by itself?

This car has a crank relay?

Does it have a black resistor pellet on the ignition key?

Has it been scanned for codes?

04-23-2013, 06:12 PM
Oddly enough, that's what happens. Sometimes it'll turn over for a second and the car will fire but not start, starter will kick out, then turn over again and it'll start, but the starter will run on for maybe half a second. It's about the craziest thing I've ever seen.

I got a wiring diagram from another guy, showing a 'crank relay' in the underhood fuse box, told my friend/the owner to pull it. He said he did, and everything was dead. (which makes sense I guess)

I can't remember if it has a chipped key or not, but it does have one or the other of the factory resistor systems, as it's got the two small wires to the lock cylinder. We haven't bypassed it yet, but was leaning towards it.

And I'm not sure the last time he scanned it, I'll have him do that when he gets home from work.

It sounds exactly like an autostart system, but he hasn't been able to find a module for one yet, and they haven't put one in since he bought the car, probably 5 years ago.

04-23-2013, 10:13 PM
Sad news to report. We'll never know what was wrong with that car, today, thanks to the Minnesota DOT's lack of interest in plowing our state's highways before people have to be at work, the radiator and engine bay filled up with snow/slushpack this morning and caused the trusty 3800 to overheat and blow a head gasket. It's been deemed not worth fixing because of a bevy nagging issues, one of which being the subject of this thread. Thanks for all the looks and time guys.

Tech II
04-23-2013, 10:47 PM
The wiring diagram I saw, did not show the crank relay....if you have one, then you have the Passkey system, with a black resistor on the ignition key....

If the relay was sticking, in other words, the contacts were touching without being powered, then when you turn the key to on, the vehicle would crank in the "on" position.....however, the starter would continue to engage even after the engine started, with a stuck relay.....since it doesn't do that, it's not the relay......so whatever grounds the relay circuit is the culprit....this is the Theft Deterrant Module circuit, which in this case, may be the BCM.....

Since the BCM, controls many electrical circuits, this would be the component I would be checking into, since you are having other electrical problems.....

A tech, who knows what he is doing, should be picked to check this out...

I'm not sure if there is a manual diagnostic mode that can give you BCM codes, or if you need a GM scan tool to read them......

You may need to take this to a GM dealership, and ask, no, demand that their best diagnostic tech gets the vehicle...

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