Garrett76Zt Posted September 27, 2003 Share Posted September 27, 2003 OK, headlights don't work. WHen I turn the switch they get 12 volts, so they have power. the headlights are not bad. When I manually ground them out they turn on. SO somewhere in the circuit they are not getting grounded. where could this be? Please help! Garrett Quote Link to comment Share on other sites More sharing options...
Guest Carrman Posted September 27, 2003 Share Posted September 27, 2003 I beleive the headlight switch controls the ground, and not the power. See if you have power with the headlight switch off. I recently set my 75 up with H4 lights and relays, and learned that they are controlled b switching grounds. Dave Quote Link to comment Share on other sites More sharing options...
Garrett76Zt Posted September 27, 2003 Author Share Posted September 27, 2003 Hey I have no power to the lights with the switch off. When the switch is turned on it gets power. So I think the ground must be somewhere else? Garrett Quote Link to comment Share on other sites More sharing options...
jimzdat Posted September 27, 2003 Share Posted September 27, 2003 The headlight switch provides 12v to the lights (via the fuse block-1 for each light) The dimmer switch is what controls the ground--make sure you don't have a loose connection there, and that the ground wire is hooked up under the column. I've also seen the solder joints on the dimmer switch break on occasion HTH, Jim Quote Link to comment Share on other sites More sharing options...
Guest Carrman Posted September 27, 2003 Share Posted September 27, 2003 "The headlight switch provides 12v to the lights (via the fuse block-1 for each light) The dimmer switch is what controls the ground" Well, I was half right....... I knew somehow grounds got switched to make things happen! Thanks for setting me straight on that Jim! Dave Quote Link to comment Share on other sites More sharing options...
TomoHawk Posted September 28, 2003 Share Posted September 28, 2003 Ok.... So where do the headlights get their ground connection? I assume it's also the ground for all the lights on the front? Quote Link to comment Share on other sites More sharing options...
spotfitz Posted September 28, 2003 Share Posted September 28, 2003 You also might want to check your high/low beam switch. I lost lights in my '77 one night and thought it was the head light switch. After pulling it apart and cleaning the connections, I still had no head lights. I then moved onto the hazard switch. That was my problem in my '74. Still no luck. I then moved to the high/low switch. Presto. Very corroded. Got another and lights work fine now. This was in the last 2 days. Hope it helps Quote Link to comment Share on other sites More sharing options...
pparaska Posted September 28, 2003 Share Posted September 28, 2003 Jim is correct. Here's the flow of electrons: Ground to common of dimmer switch High and low wires off dimmer switch to both headlights (two wires to each, headlights in parallel in this side of the circuit) Common from each headlight to the fuse box - one fuse connected to each common on the headlight Opposite sides of both fuses tighed together and connected to the headlight on/off switch. Common on headlight on/off switch to un-fused 12V from the ammeter. Ammeter to alternator output and battery. The above is close if not absolutely correct. Not sure about the ammeter and battery connections - just can't remember. Quote Link to comment Share on other sites More sharing options...
TomoHawk Posted September 29, 2003 Share Posted September 29, 2003 Here's an interesting fact about electricity/electrons: Current goes from the (+) pole to the (-) pole and the electrons travel from from the (-) pole to the (+) pole... Electrons are negatively charged, so they get attracted to the (+) pole. Quote Link to comment Share on other sites More sharing options...
jimzdat Posted September 29, 2003 Share Posted September 29, 2003 OK, it's really basic (took me about 5 minutes in MS-Paint) but here's the basic circuit for the lites. Some components are not there (fusible links, ammeter, etc) but this might help. Jim Quote Link to comment Share on other sites More sharing options...
TomoHawk Posted September 29, 2003 Share Posted September 29, 2003 THAT made sense. thanks a LOT. I think it explains why there were 2 headlight fuses, but not why there is a fusible link. Is the fusible link for the entire front? (Maybe I should go look myself.) On the other hand, why have people been suggesting that to make the headlights brighter, you should clean the ground connection. About all there is in the diagram that would degrade the performance if the lights is the wiring. In my case, the R.F. headlight seems to be shining noticeably brighter than the left. All that I can think of is some resistance in the wiring, and/or corroded contacts on the light itself. It won't be easy to get in there, it's got that plastic inner fender in the way, and it looks like a big job to get in there. Quote Link to comment Share on other sites More sharing options...
Guest Carrman Posted September 29, 2003 Share Posted September 29, 2003 You can be into the bucket area in under 20 minutes. The plastic inner fenders are quite easy to pull once you remove the wheel and tire. Did it when I converted my car to H4 lights. Dave Quote Link to comment Share on other sites More sharing options...
TomoHawk Posted September 29, 2003 Share Posted September 29, 2003 It looks like there are so many screws to remove, then the inner fender should come out. Mine has some cracks which should be fixed, at least temporarily, until I get to do the GTO conversion(many next summer.) Quote Link to comment Share on other sites More sharing options...
Guest Carrman Posted September 29, 2003 Share Posted September 29, 2003 Cordless drill with a phillips bit. Much faster than using a socket and ratchet. Dave Quote Link to comment Share on other sites More sharing options...
TomoHawk Posted September 29, 2003 Share Posted September 29, 2003 Did you notice ther are these fancy clips that hold the inner fender to the lip of the wheel well? BTW, whatever I do, I gotta get it done in one day- can't leave the car in the garage at night. Maybe I can fix one inner fender a day, or ifit doesn't rain, leave it outside unprotected (car cover.) Quote Link to comment Share on other sites More sharing options...
jimzdat Posted September 29, 2003 Share Posted September 29, 2003 And for those wishing to do a wiring harness upgrade, here's a basic diagram for that: (not my diagram) I modified this diagram slightly so I could use the stock dimmer switch easier: 1-Where it shows the Ground connected to terminals 85 on the relays, run 12V instead, switched on by headlight switch 2-where it says "from OE circuit" hook up wires from dimmer switch--dimmer switch will now ground one relay or the other, making lights go on The whole writeup can be found here: http://catalog.com/susq/other/headlamp.htm FWIW, this is the place I bought my Hella H4 conversion from--excellent service, and decent prices--would definitely recommend them. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.