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I have a 72 Delta 88. My dash & flood lights are not working. Glove box, dome and curtesy are good. I've checked the bulbs, good. I tested all the fuses at the fuse box, everything is getting power EXCEPT the fuse with the dash & flood lights!
I'm not an electrical guy.. What's my next move? Bad headlight switch, that would turn the dash & floods on. OR something at the fuse box?
Please define floodlights? Do you mean parking lamps? You are saying that there isn't any power on either side of the dash light fuse? If true check the bulkhead connector on the firewall. Google 72 GM Bulkhead connection for a look at that. Also, verify all grounds. Wiring diagrams are available for purchase online. Order yourself a hard copy as the online versions are hard to read.
By flood lights I mean the small lights that light up the radio, wiper controls etc. Same circuit also lights up the speedometer and gas gauge. Those are not working either.
I did test the fuse with the light switch on, and power on at the key.
Neither side of the fuse is getting power. All others are getting power.
I don't have a schematic for your car. I'm assuming the light circuit is the same as an A body. The taillight fuse provides power to the light switch taillight and panel lights. The little 3A fuse is powered when the panel lights are on. All indications point to a problem with your headlight switch.
It's weird, the light switch works for the headlights etc, and turns on the interior curtesy lights. So is it possible that JUST
The headlight switch has different circuits in it. The courtesy light circuit provides a switched ground to turn on the lights.
Originally Posted by Kensey
The dash lights trip is not working? I guess anything is possible, but is it likely?
Thanks again all.
The dash lights are controlled by the rheostat on the front of the switch, I suspect therein lies your problem. You can jumper 12v to the 3A fuse that feeds the dash lights and they should come on.
The parking light issue has to be internal to the switch also as both your headlights and tail lights work.
This should be a breakdown of the headlight switch:
I recently had a similar issue with mine while replacing my gauges. The dash light brightness is controlled by the rheostat in the light switch and that can become very oxidized over time. It may not actually be corroded but covered with dust and oxidation and stop working. Mine would not even turn the courtesy lights on because of so much dust build-up. Take the light switch out and clean it well with a toothbrush and electrical contact cleaner. Or just replace it. You can also try turning the dimmer back and forth for a few minutes and see if that helps. Sometimes that will clean the contacts enough to work.
OK, I did the jump wire and my floods, speedo light and etc lit up!
Would this mean it is the light switch for sure? OR are there several things that could be keeping power from the fuse in the box? I'll replace the light switch for sure, I'm just asking so I don't get my hopes up too high.
I suspect the headlight switch, but... Lets do one more test, you need to remove the switch and jumper terminal 5 to terminal 2 on the switch connector. If the dash lights come on the replace the switch. Cleaning them works for a while if the rheostat isn't open, but it will act up again.
Picking up a new headlight switch today. Figure I should have one ready once I pull the old one out.
ONE MORE random question. My car has not been hacked apart by any means, but has had some word done over the years. There is one wire that I'm not sure what it goes to, I can't find it on the wiring diagram in the OG manual.
It's red, and has a small in-line fuse. 5 amp max. Someone decided to strip the end of the wire and piggy back it into another fuse at the clip. Is this for the radio? (Which is currently not working.)
The plot thickens right... I figure this red wire has nothing to do with my flood lights though. Same issue with that wire hooked up and disconnected.
That does sound like a radio feed wire if you have an aftermarket stereo. Some stereos have the memory feed wire as red with the ignition feed as yellow and some use the opposite. You would need to check the requirements for your stereo to know which you have. Some stereos will work without the memory feed wire hooked up but will lose clock and station preset each time the ignition is turned off and some will not work without both feeds connected. Again, you would need to find out what your stereo needs.
Put in a new headlight switch. Flood lights come one, won't turn off... They'll dim by turning the ****, but not shut off when the switch is pushed all the way in. I think the switch may be junk, gonna exchange it today just to eliminate the possibility.
TWO NEW QUESTIONS:
What the hell is this??
And second, I followed the red wire with the in-line 5 AMP fuse that is just inserted into the fuse box. It come out of a connector, that leads to a thick black wire that seems to come from the steering column. Ignition switch?
The black box and four-wire connector are part of an aftermarket Dana speed control unit, "cruise control". I suspect the wiring that the fuse holder is part of is also part of the Dana wiring. The On/Off switch should be on the turn signal stalk of your steering column, that is why the power feed wire is routed to the column. If it is not working I may be able to help you troubleshoot it. It should not cause electrical issues as long as it was installed correctly. Sounds like it was not installed cleanly, but it may still be connected correctly. I know that sounds contradictory but it can be connected right but still be a sloppy install. If everything is still there, it may be repairable.
The four-wire connector is for speed controls like "set", "accelerate", and "cancel". The other wiring is for power, brake light, speed sensor, engine speed sensor and such.
Oh yeah, if your dash lights won't turn off after the new light switch was installed, you either have a bad switch or you have power feeding back into your lighting circuit somewhere else. You're gonna have to check as much of the grey wiring connections as you can find behind your dash. You should have connections at the glove compartment, ash tray, all of your flood lights, the instrument panel. There should also be at least one spare connector under the dash for extra connections. Make sure there are no connections between the Dana control module and that grey wire. That grey wire is often mistaken for a black ground wire by aftermarket electronics installers!
You can disconnect the power to the cruise unit and it will remain inactive. If you try to remove it, you will need to remove everything down to the wire connections and actuator. All or nothing kinda thing.
I did some looking at the wiring diagrams on-line for Dana products and some do tie into the lighting circuit so follow all of the wires from the cruise unit (there aren't many of them) and see if any of them are connected to the grey wire for your dash lights. If it is, disconnect it and see if that will resolve your lighting issue.
Good it worked. That 4 wire plug is, like said above, probably part of that Dana unit. That plug is computer hardware format, used to be used for CD drives and hard drives and fans, but now has been replaced by a newer format for everything but fans. It's 12V.
June 24th, 2018, 06:35 PM
