I have a 1989 420 SEL. The alarm intermittently comes on while starting or even while driving. How do I find and debilitate the alarm. I don’t really need the darn thing.
The intermittent alarms are caused by aging sensors, most likely one is the trunk lid sensor.
The system can be trouble shot, but it can become somewhat involved and time consuming.
Most people just disable the thing.
A temporary fix that some people use is to simply pull fuse #15, but you end up disabling other items as well. It’s a much better fix to just disable the alarm at the source.
So, I’ll try and walk you through this:
- Open the front passenger door.
- Reach up to the top of the floor mat below the glove compartment and pull
it down and back.
- Repeat step two if you don’t see a black plastic panel (there may be two
layers if you have an accessory floor mat).
- Remove the nut at the bottom of the black plastic panel, which is way
down in a hole (long nosed pliers may work, but a 10mm socket with an
extension is the right tool).
- Get that black panel out of the way and don’t lose that nut!
- Remove the tie wrap from the black box on the left (ignore the two silver
boxes on your right - air bag stuff).
NOTE: The tie wrap is removable -you don’t have to cut it)
- Gently pry the two connectors away from the control box, no clips
- Replace the tie wrap.
- Replace the panel and nut (its plastic - don’t make it too tight).
- Put the floor mat(s) back in place.
- Close the front passenger door.
- Put fuse #15 back is you had temporarily removed it.