Full Version: 914 alternator light on when I step on brake
I have been having issues with my starter. I doesnt start as usually as if it struggles. I check battery voltage with car off and it's around 12.35 with car running at 12.80 volts and with all lights on and car running it goes down to 12.40 volts. I also notice when I am driving and I step on brake the alternator light dims on. Has anybody had this problem.
With the car running and all the lights off, you should be getting closer to 13.8 (measured at the battery).
QUOTE(McMark @ Dec 6 2010, 01:32 PM) 
With the car running and all the lights off, you should be getting closer to 13.8 (measured at the battery).
When I turn on vehicle it doesn't start quickly it cranks slowly then turns on. I can't explain the alternator light turning on when I step on brake
Check your ground strap from the battery to the body, clean it
Check your ground strap from the transmission to the body, clean it.
Take both off and use a wire brush or a dremel with a wire brush to get down to bare metal.
I replaced the transmission ground strap with a new one from the FLAPS store...the older braided straps tend to not work well after 40 years.
that may explain why you are having a hard time starting and you are drawing to much current.
The low charging issue (you should have 12.7 -13.7 volts when charging)
could be more dirty connections (clean both at the battery, clean all of them at the starter also.
chase the wire from the alternator to the relay board and clean that one with electrical contact cleaner and a tooth brush.
These old german cars are well known for needing some cleaning of the grounds and plugs after 40 years on earth. Any car needs this.
RIch
Check your ground strap from the transmission to the body, clean it.
Take both off and use a wire brush or a dremel with a wire brush to get down to bare metal.
I replaced the transmission ground strap with a new one from the FLAPS store...the older braided straps tend to not work well after 40 years.
that may explain why you are having a hard time starting and you are drawing to much current.
The low charging issue (you should have 12.7 -13.7 volts when charging)
could be more dirty connections (clean both at the battery, clean all of them at the starter also.
chase the wire from the alternator to the relay board and clean that one with electrical contact cleaner and a tooth brush.
These old german cars are well known for needing some cleaning of the grounds and plugs after 40 years on earth. Any car needs this.
RIch
Cleaning connections is a GREAT maintenance task on these cars. Often neglected, and usually quite helpful.
Just checked voltage 12.5 volts car off, running 14 volts. Running with lights on. 13.5 volts. I also noticed that the alternator light is on I removed the gauge and noticed the bulb was dim very low and when I step on the brake it lights up further.
remove and clean your fuses...they may look good, but they may have enough crud in there to cause a problem
Rich
Rich
QUOTE(recko911 @ Dec 6 2010, 08:30 PM)
Just checked voltage 12.5 volts car off, running 14 volts. Running with lights on. 13.5 volts. I also noticed that the alternator light is on I removed the gauge and noticed the bulb was dim very low and when I step on the brake it lights up further.
The bulb voltage is the difference between the battery voltage and the voltage at the voltage regulator. Remove the gauge and measure each terminal of the bulb to ground. Sounds like you have connections that have oxidized and are acting resistive.
Clean your grounds and maybe even your battery terminals.
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