Hello I have a question I own a 1967 Mercury Cougar my dash lights are not coming on. I checked the fuse box there’s no power going to it so I replace the headlight switch. Still I have no power going to the 2.5 fuse. What am I doing wrong? When I plugged in the new headlight switch the 2.5 fuse box had power for a couple of minutes but after it blew my 2.5 fuse but now I have no power again. Please help this is a bit frustrating to figure out thanks in advance
Do you have an aftermarket radio?
I do not have a radio at all. I’ve heard that maybe the blue and red wire is maybe broken along the way but not sure. I guess Im looking for the easiest way to fix the problem without having to untapped all the wires. All i really have plugged is the standard console lights
Power goes from the battery to the fuse box then to the switch. Since you don’t have a radio chances are that the harness is flopping around behind the dash and possibly touching metal which would blow the fuse. Don’t put in a bigger fuse. The best way to trouble shoot this is to take an old fuse, break out the glass center, solder a wire to each end and then attach the end of each wire to the bulb. If you have a short the bulb will light up instead of blowing a fuse. This way you can move wires around and see what is happening. Unless the original wiring has been burnt up the probability of a bad wire inside the harness is pretty close to infinitesimally small. The most probable cause will be a wire that has been pulled across a sharp metal edge.
From what I have read the power to that fuse comes out of the light switch which I replaced. what color are the radio wires?
Ummmm…power for dash lamps is converted from battery power at the headlight switch, which goes to one side of the fuse box. The other side of the fuse box goes to all of the dash lamps.
Wire colors for factory radio are yellow/black (fused ACC power) and blue/red(dash lamps).
LOL! We are talking about different lights. I was thinking of the courtesy lights under the dash, not the instrument panel lights that are controlled by the potentiometer or fader in the headlight switch. The under dash lights, the door mounted lights, glove box light, rear opera lights, and radio light that are all on the same fuse.
From an engineering standpoint it is really weird that the fuse wouldn’t be between the power source and the switch to protect the entire circuit. If there is a short between the switch and the fuse box it would be fatal to the switch or the wire connecting it. Any one have a schematic that shows this fuse and circuit?
From Mach1 Driver on the 69 forum. Although not exact for Cougars, the basic schematic holds for much of the wiring.
I have the same issue, but my fuse is not blown. I have no power at the fuse box for the dash lights. I have untaped the wires but blue/red stripe wire from the fuse box to headlight switch looks good. I also don’t have a radio and I have installed a new headlight switch. The dash lights were working at one point. I’m so confused what is the next step.
The fuse panel may be so corroded on that terminal that no power is getting to the fuse. I have had this problem on several Cougars over the years. The easiest fix is to use a small Dremel stone and grind away the corrosion where the fuse touches the spring steel. Then put Vaseline on the terminal before installing the fuse to keep it from corroding again.
It’s tough to get close enough to view the fuse panel much less to work on it without removing the driver’s seat first.
I unbolted the fuse panel and I took some sandpaper and sanded the back connection where the wires go to the fuse box. Still I had no power to the 2.5 fuse. Could there be a possibility that my headlight switch burnt again??