1990 Dodge Caravan

I just got the exhaust system replaced (muffler & pipeing) brought the car home and now the brakes aren't working. I think the brake adjustment line must have been tampered with. Master Cylinder level is full and no visual leaks in the area. Brake warning light is on and very little pumping action left to stop vehicle. I made this adjustment on my '75 Honda but need to know where to find it on the Caravan. Can't afford a tow or the cost of more repairs so I want to try adjusting the line just incase this is the problem and to help make it more driveable if I have to take it to a mechanic. My kids use the car on occassion so it has to be safe.

Thanks for your help,
I can do a lot of basic repairs and maintenance and know the parts, etc. : Shock:
May 11, 2007.

The reasons for the brake light switch are low fluid or parking brake engaged or partially engaged, not to say a switch is faulty.

As far as adjustment for the mechanical brakes, you would want to remove the rear drums, clean them with brake clean, and turn the adjuster wheel until the drum has a little drag on it when spinning the drum. I just don't see a connection the light from a mechanical adjustment.