BenzWorld Junior Member
Date registered: Jun 2008
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03 E500 Electrical problems since main battery change
Had the main battery changed out on my E500: have problems since change. smart keys do not open or lock doors when the car is warmed up (work fine cold) and cruise on instrument cluster lights up from 0MPH to 120MPH when I use one of the two keys for car....cruise is off and car is sitting in my driveway. Below are some of theings I tried today. Everything worked fine before I had the batttery changed out.
1/14/12: Replaced main battery again with another one...no change. checked aux battery shows about 13 volts.
Checked all fuses in both front and rear boxes with meter(all good)...reseated relays in rear box. No change.
Pulled and checked battery voltage on all key batteries...shows 3+ volts on each battery.
Both Keys lock and unlock car when the car is cold (first thing in morning or sitting for a few hours (live in the N/east cools down quick): locked and unlocked several times: no issues) When it warms up neither key works the door locks...both still start the car (with the one key still lighting up the cruise from 0MPH to 120MPH....assume they left the key in when they changed the battery...key I guess is done....)
Have no idea what it could be.....as I mentioned both worked fine before initial battery change....something electronic was fryed....where to start....will keep digging.......open for suggestions...thanks.