High Beams Stay On When Car Turned Off Mystery

[ThunderStangLX]

1997 Thunderbird, high beams work fine when car running and turn on and off with the stalk but when you turn the car off and the headlights switch to the off position (and the running lights position) the high beam (blue icon) indicator on the dash turns on and the high beams stay on with the car off. Removing the headlight relay in the engine bay relay/fuse box does not turn the lights off either.

 

[Grog6]

If it's a switch with delayed entry, It may be bad. Do you have an aftermarket alarm?

 

[ThunderStangLX]

If it's a switch with delayed entry, It may be bad. Do you have an aftermarket alarm?

No aftermarket alarm.

 

[theterminator93]

The Canadian MN12s have a DRL circuit that the US models doesn't have. Perhaps it's related to that...?

 

[XR7-4.6]

There aren’t any relays for the headlights from the factory btw, just the fuse in the power distribution box.

An issue with the DRLs is a very good point, I was leaning towards a bad multifunction switch but that’s now what I’d look at, it runs the high beams pulsed, but what I’m not sure about is whether the high beam indicator is on with DRLs, I wouldn’t expect so but being in the states I’ve never been in a MN12 equipped with it

 

[3_97_Sports]

no the high beam indicator does not turn on when your daytime running lights are on.
it does if you flash to pass, like yours probably.

I have no idea about this font, and how I did it.

 

[Grog6]

If you have the delayed exit feature, the actual lightswitch has a relay to do the delay function. But the only switch for the highbeams is the mfs.
iirc, pulling the stalk in to flash works with key off. Care to check anyone?

Anyway, unplug the mfs and see if it goes out.

 

[ThunderStangLX]

If you have the delayed exit feature, the actual lightswitch has a relay to do the delay function. But the only switch for the highbeams is the mfs.
iirc, pulling the stalk in to flash works with key off. Care to check anyone?

Anyway, unplug the mfs and see if it goes out.

Don't have the delayed exit feature.

After disconnecting battery and reconnecting no more highbeams staying on for last day but blinkers are erratic and working strange, will try to unplug mfs and report back.

 

[Derphound01]

My bet is a failing MFS.

 

[XR7-4.6]

Yeah that was my first instinct and I’m back to it, it must have an internal short