: Strange problem
11-08-04, 09:33 AM
I have a 1969 Cadillac hearse 3-way loader with a 472. I recently noticed that the wipers and the radio only work if the headlights are on. This just started happening. Maybe a short in the headlight switch? It doesn't matter if the car is running. Even shut off it does it. You can have the radio on and playing with the headlights on and as soon as you shut off the headlights the radio dies. I noticed at start up the GEN light stays on until you turn the headlights on then it goes out. The key does not have to be on for the radio to work. Key is off. Turn on radio, nothing. Leave radio on then turn on headlights, bingo radio comes on but the key is still off. Sounds like maybe a short in the column. Maybe turn indicator switch? Was working on the turn indicator arm installing a skull head on the end and it required some sawing of the turn indicator arm. Wondering if the vibration may have shorted something inside. Anybody have any ideas I'm all ears. Thanks. :rolleyes2
11-08-04, 11:07 AM
A lot of times you can find stupid stuff like that just by wiggling wires around. I would tend to think that the ground circuit for the radio might be compromised and it is pulling it out of the headlight circuit somehow.
Maybe see if the radio/wipers are lacking power or ground. I'm assuming they're on the same fuse.
11-08-04, 12:16 PM
Has the wiring been modified anywhere from what you can see? Wherever you see a wirenut or a crimp connector be suspicious.....
11-08-04, 02:43 PM
No modifications that I can see so far. I'm still crawling around under the dash. The radio and wipers have seperate fuses at the fuse panel under the dash. The wipers and radio are both fed from the acc. side of the ignition switch. Wonder if it has anything to do with that. like I said maybe the turn indicator switch? I'm thinking when I cut the end of the turn signal lever if somehow I shorted something in the turn indicator switch. On my 1996 Cadillac Seville STS the LED brake light in the trunk lid would light but not the ones in the tail lights. I would fiddle with it and get all of them to work but then the tailights would stop and only the LED in the trunk lid would work. After some internet surfing I came across an article that said the turn indicator switch could be the problem. I went out to the car and when you used the signal for a right hand turn BINGO all the brake lights would work. Then if you used the signal for a left hand turn the taillights quit working and only the LED in the trunk lid worked. Turned it back for a right hand turn and they all worked again. My wife has to make a left hand turn into our driveway at night and was using her signal therefor in the morning the brake lights would be screwy. Took it to the dealer and had the switch replaced and all is well. I would have done it myself but did not want to mess with the airbag. I never would have suspected the turn indicator switch but sure enough that was it. In looking at the old one alot of stuff runs through that switch. Being the fact that I was cutting on the turn indicator lever and then the problem developed I'm thinking maybe that is it. Not sure but maybe.
11-08-04, 05:55 PM
Bet you anything it's gonna turn out to be something stupid. It's hard to believe cutting that lever would do that but you never know. Maybe try unplugging the items in question esp. the signal switch one at a time and see if anything changes. Maybe there's some ghosts in there haunting that baby!! :eek:
11-08-04, 11:22 PM
check the fuses and relays once I blew a fuses back in on its self and the interior lights would come on when you shut the doors and off when they were open realy stumped me then by accident I found that blown fuse also some wire diagrams could be of some help
11-09-04, 11:46 AM
What happens when you remove the fuse(s) from the headlights I wonder? Do things begin to happen with just the headlight switch in the "on" position? Or do the headlights have to have current?
I'm with you. Sounds like a short in the column or fusebox area - which would easily explain why the radio/wipers would work without the key. But why would they NOT work WITHOUT the headlights I wonder? Unless a fuse is blown as well.
Ok, here's an idea.
The healight switch might be crossed with the ACC circuit. So having the healight switch on is now equivilent to having the key in the ACC position.
See what happens without those headlight fuses. Might help you narrow the problem area to the switch.
11-09-04, 01:25 PM
I'll try that. I'm also wondering if maybe the ignition switch is bad. If you turn it to the ACC position nothing happens as far as trying to get the radio to play or the wipers to work. Pull on the headlights and all is fine. Working on the car today installing a new set of curtains I'll see if I have enough time I'll check it without the fuse. If I don't get to it today I will first thing in the morning and I'll be back to let you know what I find out. Is there more than one fuse for the headlights. The only one I know of is in the fuse panel under the dash. Thanks for all the input it's appreciated.
11-09-04, 03:15 PM
I was thinking there would be seperate fuses for high/low beams under the hood in a seperate box. I wish we had a wiring diagram.
11-09-04, 03:50 PM
I've got a service manual. I'll scan some diagrams and send them to ya. Email me at firstname.lastname@example.org Thanks for the help.
11-10-04, 12:01 AM
Wait a sec, I thought the only thing that came from the fuse box dealing with the lights was the parking lights and dash lights. IIRC the headlights get a constant 12v and have a circut breaker internal to the switch, no fuse to remove
11-11-04, 03:10 PM
Radio and wipers are on different fuses. The only thing they have in common is that they are both supposed to be powered by the ACC circuit, which obviously isn't working properly.
DaveSmed you're right about the headlights.
Maybe see if the radio/wipers are lacking power or ground. I'm assuming they're on the same fuse.
11-17-04, 04:20 AM
When checking for voltage as suggested in my service manual I
turned the key on and nothing at the yellow wire at the wiper motor. Pulled
out the headlight switch and got a reading of 10.08 volts. Pushed the light
switch back in and a reading of 0. Turned the headlights on again and a
reading of 10.08. Why is the light switch preventing the current from
reaching the wiper motor? I've got to look at the schematics. When opening
the switch the current flows to the yellow wire. Is the headlight switch in
line with the wiper motor? If it is then maybe there is a short in the
headlight switch that only allows the current to pass when the switch is on.
When you try to turn on the interior lights by turning the switch nothing
happens. I got under there and looked and someone cut a white wire coming
from the switch that appears to be the one for the interior lights. I say
this because as I turn the switch to engage the interior light I can
actually see the mechanism that clicks the contact point closed to give the
interior lights current and that is where this white wire originates.. Maybe
this is something the funeral home did. At any rate I don't think that has
anything to do with it. Worst case scenario when it rains drive with the
headlights on. Actually in the state of Florida the law is that if you have
to run your wipers you must turn your headlights on. The ignition switch I replaced has
made a difference. Now when cranking the car you can see all the gauge
lights (oil, gen, brakes, water temp.) all come on momentarily like they
should. Didn't do that before. Also the GEN light does not stay on anymore.
Turn the key back to ACC and everything works. So that is definitely an
improvement and something that needed to be fixed. Well back to looking at
these diagrams to try and see if that headlight switch is somehow in line
with the wipers.
11-17-04, 04:53 AM
Have you tried pulling the plug on the headlight switch, then see if the wipers work normally? It would seem that the voltage that belongs at the wiper motor must be going somewhere.
11-20-04, 05:17 AM
Barge tried your suggestion. unplugged the headlights and turned on the wipers and nothing happened. No wipers. While I had the harness unplugged I checked a yellow wire that was part of it and found the same 10.08 volts that I found at the yellow wire in the harness that plugs to the wiper motor. HMMMMM......... Strange problem, strange problem indeed.
11-21-04, 09:24 PM
So now are the wipers lacking power or ground with the headlight switch unplugged? :hmm:
11-22-04, 04:20 AM
Yes no power to wipers. The ground is via a ground strap at the wiper motor and all looks good there.
11-22-04, 03:37 PM
They must have connected the yellow wire for the headlights to the yellow wire for the wipers somehow. Disconnect the yellow wire from the fuse block behind the wiper fuse and post up what happens. My bet is the wipers still come on with the headlights, even though they should have no power at all.
11-24-04, 07:42 AM
Post a pic of the wiring diagram for these items if you can. Maybe one of us will see something that leads to a solution.
12-07-04, 12:24 AM
The white wire that they cut was the ground wire that completes the circuit for the interior lights. The car has some electrical components that seek a ground and others work by providing power to them and are grounded. The interior lighting is powered all the time and when you open a door, the door button provides a path to ground. First off, I would reconnect the broken yellow wire. Then I would check to see if the wiper motor has been removed and replaced. The wiper motor is set with rubber grommets and it is important that only the proper area of the wiper motor be grounded. If all this is OK, then I would read what each fuse does and test that appliance with the fuse removed. The appliance shouldn't work with the fuse removed. If you find that it is working, that indicates that there is a crossed wire somewhere. The problem with Commercial Chassis cars is that the body builders would extend the wiring and there is no understanding of how they accomplished some of the things that they did. Wiring diagrams from the body builders are seldom found. Also look in places that you normally wouldn't think that there should be a fuse, because they were known to install in-line fuses in the rear compartments. I notice that your car is a 3 way.... if it has a powered electric table, I would check out the wiring to it to make sure that there is no problems there. Wiring problems are a difficult task to diagnosis, but with perseverance, it can be done. Just remember that it is important not to cut wires, but to make sure that the integrity of the original wiring is maintained. Too often people cut the wiring and figure that by bypassing a section that they will resolve the problem. In these instances they just create more problems for the future. Junkman....
12-09-04, 06:55 AM
Well let's see where do I start? After driving the car for a while one night the instrument panel lights went off. The wipers had begun working correctly. After a day or so I decided to try to find the problem. I removed the fuse block and turned it over. I could see where the wire on the bottom of all the ones coming in had gotten hot and begun melting some of the wires together. It was the green with black stripe wire. Tailights is what the fuse block said. The yellow wire for the wipers had actually melted to the point of it having exposed areas and was touching over to the green and black. I suspect this was my problem with the wipers. I took the dash out and began tracing the green and black wire to make sure there were no spots that were melted and grounding out. When you would turn on the headlights the spade connector on the green and black wire that connects to the fuse block would get extremely hot until the fuse would pop. After tracing the wire all the way to the headlight switch all looked good. I removed the sill plate on the drivers side to see if the wire ran under here to the back for the taillights. Thinking maybe it got pinched. Nope it runs more directly under the seat. So I decided to go to the back of the car. I'm looking at the tail lights and the license plate lights. By the way how do you remove the lens from the tailight? I'll have to look that one up in my service manual. Anyways I digress, I'm looking at the license plate lights when I notice the plastic lens is a little "bubbled" like it may have gotten hot. I remove the lens and pull out the socket and voila. The rubber insulator on the socket had melted and the wire was coroded and grounding out to the bumper. I removed the old socket and left the wire hanging, so it wouldn't touch anything, turned on the lights and everything worked. Checked the spade connector on the green and black wire and it was cool as a cucumber. I had replaced bulbs in these months ago. I had to drill out the old screws to remove the lens's and replaced them with a slightly bigger threaded screw. I used some liquid tape to mend the few bare spots by the fuse block and reassembled the dash. I purchased A new socket and installed it using the old assembly parts. It is a one lead socket that gets it's ground when you tighten the screws to the lens. Tested everything and all is good. (so far) This was one of those problems that just took time and patience to figure out. Thanks to all of you who offered sugestions. I'm going to keep an eye on that light and see what happens. Got a little more work to do as far as finishing up the dash reinstall but nothing major. I'm hoping this was the culprit. :thumbsup: