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· Registered
E350CDI, SL600, 500SE LPG, 500SL-32, SL500, Range Rover V8 LPG, Land Rover S2
611 Posts
Discussion Starter · #1 ·
Hi everyone

I've been scratching my head about this one (2003 SL500):

(1) Left-hand xenon headlamp cycles on/off rhythmically like an indicator flashing when I rev more than about 1000rpm When the car is standing idling or moving very slowly the headlamp is fine. Rev it (moving or standing still) and it flashes until it faults out, sometimes giving an error message on the instruments. I have changed (a) entire headlamp, (b) igniter, (c) bulbs. No effect.

I have never heard of this before.

(2) When standing idle for a day or two I get the message (picture of battery) "electrical consumers switched off". Usual shutdown of high power accessories. I have changed the rear battery. When I go for a drive the message stays on and the electrical consumers stay off - in other words it doesn't reset itself. The only way to remove the problem is to charge the rear battery.

Might the two be related?

I suspect the battery stabilization / charge split unit, but could be completely wrong.

Does anyone have any ideas? I am baffled.



· Coupe/Convertible Forums Moderator
CURRENT: 2011 SL550 FORMER: C300, ML350, CLK550 Cabriolet, C240, ML320, 300TD
25,452 Posts
If get it hooked up to SDS and check the battery system. There could be a problem with the BNS (battery congrol module)

· Premium Member
SL55, 300SE, GL450, Daytona 955i
10,334 Posts
Is is either charging system being messed up and generating under voltage condition, or Xenon components voltage regulator on their way out, or loose physical grounding nut.

While labor intensive (bumper needs out) but its the least expensive way to troubleshoot: swap bulbs, then swap ballasts, then swap igniters, and see if the problem migrates.

Trace ground points on the fender area, and make sure they are tight and clean.

As mentioned, scan the car, and look for codes regarding voltage in BNS and SAM modules.
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