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Electronics? Trip odometer and heater reset automatically

Posted: Sun Aug 30, 2015 7:44 pm
by littleyoh
Hi all,

we recently moved from Germany to Vancouver and bought an L400 (1994) for trips around beautiful BC. Unfortunately, shortly after our purchase, strange things started to happen. First, the radio didn't start anymore and the digital clock stayed dark. Shortly after that, we realized that the trip odometer resets itself to 0 km every time we switch off the motor. Also the heater/AC is reset every time. When we turn the ignition on again, the heater is set to 25°C and the AC is on irrespective of what we used as settings before. The same happens again, when we start the motor. All this did not happen when we bought the car.

I don't know if the radio/clock problem is connected to the odometer/heater problem, but both seem to be electronically problems. Does anybody have an idea what could cause these problems and what it would take to fix them. The car drives fine, but we don't want to make anything worse.

Thanks for any help

Jojo and Sandra

Re: Electronics? Trip odometer and heater reset automatically

Posted: Wed Sep 02, 2015 4:36 am
by Big-Bird
All the electronics you listed draw power from the battery to maintain memory settings so if it was me I would:

Check all fuses and relays under the hood with a multimeter.
Check all fuses under the dash as well.
Remove the steering column cover and verify all ignition switch wires are firmly soldered, then check the wires for cracks.
Pull the stereo and check there is constant power on one wire when the ignition is off..(memory power) need wire schematic.

Start with these.

Re: Electronics? Trip odometer and heater reset automatically

Posted: Thu Sep 03, 2015 6:15 pm
by littleyoh
Thanks for the tip. I hope we will find anything

Re: Electronics? Trip odometer and heater reset automatically

Posted: Wed Sep 09, 2015 3:39 pm
by littleyoh
Thanks again. It was a blown fuse. I had already checked the fuses visually without finding the bad one, but the multimeter finally gave me the right hint

Re: Electronics? Trip odometer and heater reset automatically

Posted: Wed Sep 09, 2015 5:51 pm
by Big-Bird
Glad you found the problem, fuses can be tricky sometimes to check visually. It's always best to test them across the tops for conductivity..,that's why they have the exposed tips.☺