Fuel Gauge AND Brake Warning

[carusocruiser]

Okay so I checked all the methods that is posted here on the fuel gauge and still get nothing. It is a dual tank set up on a 67 F250. I have NOTHING at the cab tank BUT there is current at the IPVR on BOTH sides and nothing changes whent the swicth is flipped.
SO odds of it being a swith or sending unit?

Second someone cut the brake warning green wire and when it is hooked up it is lit. My understanding this is for the brake MC only and not park brake and my be due to a postion on the swith in the MC.

Any help??

Thanks

Joe

[tbone6]

Second someone cut the brake warning green wire and when it is hooked up it is lit. My understanding this is for the brake MC only and not park brake and my be due to a postion on the swith in the MC.

The light staying on is usually due to a bad brake warning lamp switch in the brake pressure differential valve (as long as the rest of the system is good). The MC does not have a direct influence over the light.

Quoted from this link http://fordification.com/forum/viewtopi ... 4&p=280399 "Should a failure of the rear brake system occur, hydraulic fluid pressure in the rear brake system would drop. During brake pedal operation, the fluid pressure buildup of the front brake system would force the differential valve toward the low pressure area (secondary system outlet port). Movement of the differential valve forces the switch plunger upward over the taper shoulder to close the switch electrical contacts and lights the warning lamp, signaling a brake system failure." The article talks about rear brake failure, but it works the same way for front or rear failure.

The valve shuttles to one side or the other (blocking front or rear brake fluid) if you lose brake pressure to ensure you have some braking to the remaining good system. If you follow the brake lines from the MC down you will find the valve attached to your frame just a foot or two after they turn towards the rear. The valve will have 2 wires coming out of the top. You can remove the switch and replace it with no loss of fluid. The other option, assuming your brake system is good, is to disable the switch to keep the light from staying on (by cutting the wire ). On my truck, I have the plug disconnected at the switch and secured. The valves are hard to come by so don't remove it and toss it. They can usually be rebuilt, if necessary.

brakeblock-valve.jpg

By the way, a green wire on the brake warning light indicates the wire has been replaced at some point.