Brake Light question

[Daral]

I finished all the wiring and tested it today. Everything is working except the brake lights, flashers and fuel gauge. The brake lights are my first concern. If it is a bad switch, a direct connection across the two switch wires should turn on the brake lights, correct? If that is correct, then it isn't the switch. Any suggestions?

[edwardb]

That's correct. Directly connecting the two brake light wires should light the lights. I assume Ron Francis harness? (Always a good idea to specify for electrical questions.) If so, brake light is a battery circuit, meaning it should be on at all times regardless of ignition switch position. The orange brake light wire should be +12V. If it's not, then your troubleshooting goes that direction. Fuse. Battery connection via the ignition switch, etc. Trace it back via the wiring harness diagram. If the orange wire has +12V, then something with the lighting circuit. So work out that direction.

[Daral]

Thanks Edwardb. yes, it is a Ron Francis harness. I didn't remember that it was a battery circuit. I will track down my orange brake light wire and test it for 12V. Should I have power to the switch or is that a ground?

Where should I start with my fuel gauge? All my other gauges work so I think it is wired correctly.

[runamuk]

Where should I start with my fuel gauge? All my other gauges work so I think it is wired correctly.

Do a search on this forum. A couple of people have found one of the connectors where the wires are mis-pinned. I'm not sure if the connector is in the dash harness or the one that goes back to the fuel tank, but you can spot that the wires do not mate at the connector.

[edwardb]

Thanks Edwardb. yes, it is a Ron Francis harness. I didn't remember that it was a battery circuit. I will track down my orange brake light wire and test it for 12V. Should I have power to the switch or is that a ground?

Where should I start with my fuel gauge? All my other gauges work so I think it is wired correctly.

You shouldn't have to "track down" the orange brake light wire. It's one of the two wires attached to your brake light switch. It should have always on +12 (battery circuit) and the other wire on the brake light switch is the +12V input for your lights. So, brake light switch closes, +12V goes to the lights. The lights are grounded separately. So back to my original advice, see if you have +12V on the orange wire. If you don't, trace backwards. If you do, then trace toward the lights. The comment about the instruction manual error for the switch terminals is valid. But if you touch the two wires together separate from the switch and the brake lights don't work, then the switch or switch wiring isn't the issue.

For your fuel gauge, Speedhut (Vintage) gauges? If so, did you follow the instructions to calibrate the gauge?

[Daral]

I found the brake light problem. No voltage at the switch.......Blown fuse. Fortunately, it was the first thing I looked for. Since I thought it was wired through the ignition, I probably blew it when I soldered the wires to the taillights. The new one seems to be holding.

My fuel gauge needle jumps when I power on the car so I think it is wired correctly. I didn't realize I needed to calibrate the fuel gauge. I found the Speedhut instructions. Is the Ohm range I need 16-158 (Fords 87-present on the Speedhut table)?

[Daral]

Do a search on this forum. A couple of people have found one of the connectors where the wires are mis-pinned. I'm not sure if the connector is in the dash harness or the one that goes back to the fuel tank, but you can spot that the wires do not mate at the connector.

I calibrated my fuel gauge, but it still doesn't register any gas in the tank. I must have the connector problem too. I will need to wait until the body comes back off for paint to correct that. Thanks for your help.