I'm looking at buying a fairly clean 88 mustang with a mild motor and a t5. Only deal with it is that the headlights don't work and when you pull the headlight switch the radio power cuts out. Could this be a huge labor intensive deal? I need a car quick that isn't a project and this car is in my price range. I know this is ghetto but could I just take a 12v supply and splice it to the headlights on a toggle as a temporary fix? At least until I can dig through everything ad figure it out permanently. Any help appreciated.
You have to be careful since most headlight circuits use a relay to operate, as current draw is quite high. It is possible to splice in a high current switch, but you have to know where to splice it in, otherwise you could cause more problems. Thing with trouble shooting wiring, it can be very time consuming and unless you know what you are doing, you can cause more issues, even with a wiring diagram. It could be something as simple as a bad ground, bad switch/relay, fuse, broken wire...... With the problems of the Mustang, unless you know the history of the car, who knows what other "hidden" issues there could be! Especially since you are looking for a rtr car ASAP, perhaps this may not be the car for you? JMO, Good luck!
The part that is weird to me is that the radio power cuts out when the headlights are turned on.....maybe they wired in the radio power on the headlight circuit? Guess my first step would be to unhook the radio and try the lights.
Sounds like a possible ground issue... The radio won't be causing it... BUT as mentioned the head light and also signal/high low light switch give problems in these vehicles... Why??? Mostly because they(or any other Ford I know of) don't use relays to switch the current, all handled by the switches(well there's usually a flash to pass relay, but it isn't doing anything 99.9999% of the time) ... I'm adding relays to my Comet and also also need to do so on my '88 T-Bird, which uses same circuit as Stang... All this said your proposed rig for the lights should work, Red/Black is Lo & Lt Green/Black is Hi beams..
