Headlights on, display off
Thread Starter
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Tuned
Joined: Aug 2002
Posts: 442
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From: Palmyra
Headlights on, display off
I've got a factory am/fm cassette in my 93 F150. I had the problem with the display not working all the time (you could thump the radio or dash and it would come back for a few minutes). Sounded like a bad solder joint somewhere, so I pulled the radio and traced the wires from the backlight for the display and resoldered the joints. I put the radio back in and now the display works fine, UNTIL I turn on the headlights. Now the display (which I now know is just powered by the backlight) goes out when the headlights are turned on. Any ideas what could be going on here? Thanks!
Posting Guru
Joined: May 2002
Posts: 1,673
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From: Chicago Area
Well, of course, they're just supposed to dim when the headlights are on, so I would suspect you've still got an open somewhere on that board. This is difficult to fix because the traces and anular rings (where the wires connect) are so thin. If you can locate the crack you might try to bridge it using a small fine wire.
I am in the printed circuit business and the difference in the expansion of the base laminate compared to the metal is a continuing problem. This is particularly true when a board is outside in the cold and then gets hot in operation.
And sorry, I have no idea where you can get a replacement board--probably somewhere in China. If I sound bitter, it's only because I'm making a lot less money since they closed Motorola in Harvard and Delco Electronics in Kokomo!
Good luck!
I am in the printed circuit business and the difference in the expansion of the base laminate compared to the metal is a continuing problem. This is particularly true when a board is outside in the cold and then gets hot in operation.
And sorry, I have no idea where you can get a replacement board--probably somewhere in China. If I sound bitter, it's only because I'm making a lot less money since they closed Motorola in Harvard and Delco Electronics in Kokomo!
Good luck!
Thread Starter
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Tuned
Joined: Aug 2002
Posts: 442
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From: Palmyra
Thanks for the quick reply, MrBSS. I swear I learn something new every day-- I did not know that the light was supposed to dim when the headlights were lit. That makes me have even more questions!! I imagine the dimming is actually just a voltage drop to the backlight. What circuit triggers this drop when the headlights are turned on? Is that accomplished in the headlight switch itself? If so, this may be connected to a problem I am having with the headlight switch-- when I have the headlights on and turn the switch full ccw to turn on the dome light, ALL my dash lights go out. When I turn the switch cw past the click to turn off the dome light, I have to jiggle (actually it is more like a very quick turning of the **** cw and then ccw) the light switch to get the dash lights back on. I may just replace the light switch (joy! I can break off the last remaining dash bezel clips removing the dash) and see what happens. Thanks again!
Thread Starter
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Tuned
Joined: Aug 2002
Posts: 442
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From: Palmyra
Well I had a chance to fiddle with it after work. Lo and behold, the problem now is indeed in my headlight switch. I jiggled the switch around a good bit and now have a lit up radio display, even when running the headlights. Whoda thunk it.
