dual brake warning switch

fordman · Post by **fordman** » Thu Jan 18, 2007 9:21 pm

ok several monthes ago i put a 69 wiring harness in my 67 to get it back to a better mess than it was. it turns out the harness is for model 81 and or 85. http://www.fordification.com/images/sch ... _81-85.jpg

so this harness has two puple wires coming out of the drivers side firewall that are suppose to hook to a dual brake warning switch. i don't think the 67 had a dual brake switch on it.

so should i put the dual switch on it or wire around the two purple wires to make the switch work anyway? i think i can figure out the wirning but i don't really want to start cutting things up. what about this dual warning switch then? i'm not even sure if i kept it. i can't remember.

kid · Post by **kid** » Fri Jan 19, 2007 12:44 am

67 and up with dual master cylinders had the switch. That was a Federal requirement so the people that couldn't tell that they had a brake problem could see that they had one. The wires go to what most people call the proportioning valve. It isn't one, it is the differential pressure warning switch.

fordman · Post by **fordman** » Fri Jan 19, 2007 1:09 am

yes but the original switch in the dist block is a one wire switch. this harness has the provision for a switch with two wires coming from it.

kid · Post by **kid** » Fri Jan 19, 2007 1:29 am

My 69 has two wires and you can see what's it about in that schematic.

The Older ones went to the bulb and then down to the switch and if the switch flipped to either side it grounded out.

The two wire got power from the ign switch to the light and then up to the switch so that when you turned the ignition switch to on the light woulds light to tell you it was good. Then it reverted to the old way by grounding the warning light through the warning switch to turn it on in a failure.

fordman · Post by **fordman** » Fri Jan 19, 2007 9:39 am

yes i know the wiring is out of a 69 and the truck is a 67. that why i am asking about this.

kid · Post by **kid** » Fri Jan 19, 2007 2:04 pm

Then I misunderstood what you were asking. If you want to run the dual light put a 69 switch in the block. If your block is like mine it won't come out without cutting the lines.

fordman · Post by **fordman** » Fri Jan 19, 2007 3:08 pm

i thought the valves just unscrewed out of the blocks. and i saw on at the junk yard today on a 71 it had the two purple wires going right to the valve so i will probably change the valve if i can.

ok now on to my next problem. this wiring harness is from a manual truck. so it had the backupo light switch in the engine compartment on the bottom of the column. this truck is a automatic i have the switch that goes inside the cab that hooks to the column . what am i doing with the two wire plufg that was hooked to the backup light switch in the engine compartment. i have seen the little plugs that go in those sockets is that what i need to do or is there some other way i ned to hook it up so the reverse lights will come on. i hope you guys can understand this i tried to be as clear as possible.

kid · Post by **kid** » Fri Jan 19, 2007 3:51 pm

The manual goes to the tranny the auto goes to the column. The auto also has the neutral safety wiring. Look at connector U of the diagram you are linked to, or on the Models 81 - 85 charging diagram it is connector H. H is the column connector. When the column is connected the jumpers are gone and the other end is the column switc h. Ford almost never takes any connector or wire out of a harness they just don't hook them up if they don't need it. On the Manual they routed the backup light throught it and jumpered the starter through it.