Plug on side of the Master Cylinder

[rcecarbldr]

I only recently bought my 2005 Yukon and the prior owner put a new master cylinder on it. There is a plug receptacle on the side of the reservoir but nothing plugged into it. I assume to warn if fluid is low. I do have a "service brake system" light that comes on and was wondering if that has anything to do with it? Brakes work and feel fine. I looked all around the engine bay and can't find a connector that would plug into that receptacle. Thoughs?

 

[Scottydoggs]

id get it scanned. you'll need more then a normal code scanner to see what the brake system wants. that plug end might be pushed up behind another harness. or maybe the last owner broke the plug off? hard to say we were not there lol

 

[Fless]

How about a pic of the MC and the connector side?

EDIT: I agree with getting the code to narrow it down. Also, when I looked on my '04's MC there is no connector; I have hydroboost, not vacuum assist. But when I look on RockAuto for replacement master cylinders, every one has the connector for the brake fluid level, even though my OE reservoir doesn't. The one you have is probably somewhat a universal reservoir (as replacements for mine would have).