dash break light - PeachParts Mercedes-Benz Forum

BernieBenz · #1 10-26-2005, 06:36 PM

ive done several searches for my question but havent found an answer. My red break light, next to the break sensor light on my dash will not shut off (yes the parking break is not on). it started last week while driving in rain. its on in the morning until my car is up to about 80c temp and will stay on for the rest of the day. i thought maybe something got wet because of the rain but its been doing the same thing during both wet and dry days. any ideas?

sixto · #2 10-26-2005, 08:27 PM

In some models that warning light is also used by the master cylinder fluid level sensor and the brake pad thickness sensors.

Sixto
87 300SDL

BernieBenz · #3 10-26-2005, 09:11 PM

thanks. i have an 82 300d turbo diesel.

boneheaddoctor · #4 10-26-2005, 09:48 PM

red light is fluid level in the master cylinder...the yellow is the pad sensors..in both the W116 and W123 models I have.

BluEyes · #5 10-26-2005, 11:25 PM

Check brake fluid level first.
If that's good, check to make sure that the return spring on the parking brake pedal is pulling it all the way up to engage the switch.

pawoSD · #6 10-27-2005, 12:23 AM

Floppy parking brake pedal is by far the most common cause of this light staying on. It does on our 83, mine is firm and good though.

BernieBenz · #7 10-27-2005, 03:44 PM

the level seems fine. should i pump the resevoir pump? would that help?

sokoloff · #8 10-27-2005, 05:28 PM

There are two separate reservoirs in the brake fluid container. Are you sure that both of them are full?

Len

ImBroke · #9 10-28-2005, 09:59 AM

Both of mine are full. If there is a switch for the E brake, I'm gonna check that this weekend. Mine still stops fine, just has this annoying red light..

The only other thing I can think of is when I was replacing the air cleaner mounts, I leaned on the m/c (not on purpose), maybe I bent a prong on the connector?

BernieBenz · #10 10-31-2005, 12:15 PM

yep, both of my resevoirs are full. i pumped it a few times to see what would happend and it did nothing. the break light is still on. actually all 3 of my lights stay on when i start the car up (battery, sensor and parking break) and the battery and sensor turn off when i put the car in drive but if i let it idle they stay on. i dont remember if that did that before when i started the car or if that just started recently.

pawoSD · #11 10-31-2005, 12:18 PM

Sounds like an electrical issue a brewin'. Alternator/regulator....or possibly a grounding issue.

BernieBenz · #12 10-31-2005, 12:25 PM

Quote:

Originally Posted by pawoSD

Sounds like an electrical issue a brewin'. Alternator/regulator....or possibly a grounding issue.

any ideas on how to check it? i thought those lights werent supposed to stay on that long. like i said this started during heavy rain...maybe something got wet?

BernieBenz · #13 10-31-2005, 04:34 PM

ok i did some research on the altenator and how to check it and everything came back ok. the battery read 12v off and 13.5v w the engine at 1500rpm. i cleaned and checked my battery connections and they appeared to be fine.

i double checked the haines manual and it said the light comes on to indicate the reservior tank pumps are in working order....when pumped. so i pumped it a few times and i managed to get the light to go out for a little bit but within 2 minutes it was back on.

boneheaddoctor · #14 10-31-2005, 07:08 PM

Quote:

Originally Posted by BernieBenz

ok i did some research on the altenator and how to check it and everything came back ok. the battery read 12v off and 13.5v w the engine at 1500rpm. i cleaned and checked my battery connections and they appeared to be fine.

i double checked the haines manual and it said the light comes on to indicate the reservior tank pumps are in working order....when pumped. so i pumped it a few times and i managed to get the light to go out for a little bit but within 2 minutes it was back on.

Light should NOT be on normally contrary to what you said the Haynes manual says. That manual has been known to be inacurate.