Fuel Door Opens With Ignition

bigme · #1 (**permalink**) 04-03-07, 03:34 PM

1999 DeVille - The Fuel Door opens EVERY time I turn the ignition switch to 'start' position.

Oddball annoyance here that started out intermittently, but has now become a regular issue.

Any idea where to start? I originally thought it may have been RFI messing with the keyless since it was only happening at the house. (Towers nearby) I've ruled that out, since it's happening everywhere, every time.

Had the car for going on 3 years, and this started up about a month ago.

Kinda clueless on this one, but lurking and reading other posts here have helped me solve a load of other mini-issues.

Any ideas?

Thanks,
lees

JimD · #2 (**permalink**) 04-03-07, 05:04 PM

I have no experience with your year model.

But, strange behaviour in automobile electrical control circuits can frequently be traced to corroded wiring. And ground wires in particular. The closer the wire is to the battery, the more susceptable it is to corrosion due to the presence of acid fumes.

And some control modules become unpredictable when the car battery voltage drops below a certain level (9 Volts is the threshold). How old is your car battery? Has it ever failed to crank and start the engine? I would have the battery load tested.

bigme · #3 (**permalink**) 04-03-07, 05:22 PM

No problems starting or turning over, but the battery was my first suspicion based on other posts here in the electrical forum. The OSD shows 14.1v when running, but I hadn't thought to look at that when starting. I'll check, but is that an accurate enough way to rule out the battery?

I had to change the flasher relay recently prior to that happening, which may have gone bad due to a leakin' sunroof and a particular parking position that left water on the carpet.

Corrosion or a bad switch there maybe? They are physically close, but the flasher relay kinda 'hangs' on the wiring supplying it, which was what likely carried the water to it - IF that was actually what took out the flasher. (It was dry up in there by the time I replaced it.)

My Royal Heaviness makes it a real pain to assume the position for inspection, though I have wiggled my hand up in there three times now to find no obviously loose connections. Is it possible to remove that small cluster (trunk, twilight, fuel door) from the front side?

The two fuse/relay spots in the trunk that would apply are RADIO(?) which has no fuse, and CMFRT(?) which is fine.

Thanks for the quick response. I'm subscribed to the thread. This is one of them lil thangs I'd pay someone else for just so I don't have to physically get under the dash - but it's also one of them "plug it back in and charge him for some new parts..." things too.

lees

JimD · #4 (**permalink**) 04-03-07, 05:46 PM

Quote:

Originally Posted by bigme

No problems starting or turning over, but the battery was my first suspicion based on other posts here in the electrical forum. The OSD shows 14.1v when running, but I hadn't thought to look at that when starting. I'll check, but is that an accurate enough way to rule out the battery?....

With the engine running, you are seeing alternator voltage. What you are interested in is battery-under-load voltage as in the 400+ amp load of spinning the starter motor.

Most aftermarket parts stores have the ability to load the battery with a test rig. And they are happy to do it at no charge to you.

Plus, if the battery is more than 5 years old, it is living on borrowed time.

bigme · #5 (**permalink**) 04-04-07, 09:26 AM

Interesting. I looked before I started it, and it was at 12.5, then as I drove home it went from 13.3 to 13.8.

This morning, it was at 14.1 to 14.3 as I drove to work.

I've not replaced the battery since I got it close to 3 years ago. I'm due for an earl change and a fluid check, so I'll have 'em check the battery while I'm there.

I'll report back when I find out.

Thanks
Lees

bigme · #6 (**permalink**) 05-01-07, 01:30 PM

Well, it wasn't the battery.

I'm leaning towards corrosion behind the dash near the switch.

Not wanting to risk breakin' something in that panel, does anyone know if the small trunk/fuel/headlamps cluster on the dash can be serviced from the front side, or does it have to come out from behind?

And I got another problem... Passenger side (dual zone) climate is stuck on hot... like really good 'n hot. The switch on the door has no effect, so I'm guessing either a bad switch or a stuck damper under the dash, unless there's a fuse/relay I can check. (The light on the rotary switch does come on/off as it should.) May have been this way for a while since I usually don't sit over there, and only recently have had the AC on.

Any idears?

thanks
lee