1966 Skylark. Yes, I have the wiring diagrams. Brand new light switch. Brand new bulbs all the way around, inside and out. Just after I installed the new light switch the front of the car had lights but nothing in the rear except brake lights. After laying in the trunk for a while I cleaned all connections and voila, rear dome lights and taillights work. Only the left turn signal worked, not the right. Hours later I replaced the two yellow park light bulbs in the front bumper because only one was lighting up - DMM showed power to both sockets. Voila, front parking lights work, no turn signals in the front on either side. (Sigh) Today, I re-clean and reconnect the grounds everywhere. Now I can hear the flasher unit (also new) working in both direction but only in the rear. In fact, the front parking lights come on when only the parking lights are turned on. As soon as I turn on the headlights the front parking lights go out! The rear lights are working exactly right with the park lights, brake lights (after rebuilding the switch), and turn signals all work like they should. I tested the power at the firewall bulkhead connection and the DMM shows the exact same results as when the lights are plugged in so the wiring and the grounds are good. The dimmer switch works exactly like it should and even the little red light in the dash comes on with the high beams. The only thing I haven't actually laid my hands on is the turn signal switch. What'ya think? Would a bad turn signal switch cause the funky front lights? I pulled the fuse block a while back and cleaned all of the contacts and replaced all the fuses. Help! :idea2:
Ive never came across a bad signal switch that messed up front to back. Only side to side. Not to say it isnt possible. And as far as the parking lights, IDK.
That's a thought? I don't know either. There are no front turn signals at any time no matter what position the headlight switch is in. I just checked again and the rear lights are working exactly correct in all positions, including brake lights. Headlights are also working correctly. I guess it comes down to the "bright" side of the front parking lights are not working, and, are the "low" side of the front parking lights supposed to go out with the headlights on?
The front parking lights go off when you pull the switch out for the headlights. This is the way they were designed to work. NO front parking lights with the headlights on. Tom T.
I might be way off base here but it's worth a shot. Is it possible that the (front) parking light bulb/bulbs are installed backwards? What I mean is on my 66 I think there are 2 uneven pins on the bulb to get the hi side low side lined up correctly. Could the contacts for the turn signal not be hitting the bulb since if in backwards the bulb won't go down far enough? I think on mine this happened, and the one contact at the bottom was loose enough to hit the opposite bulb contact, while the other one wasn't; even though the bulb was in backwards? Or could one of the elements in a bulb be bad, causing an "internal short" for lack of a better term? It has been 17 or 18 years so my memory may be off.
Sounds like bad grounds, but to be sure the grounds are good try this. Set up your DMM to resistance scale and connect one lead to a grounded area and the other one to the bulb socket casing with the casing in place in the housing. You should read zero Ohms. If you don't, the problem is the ground. If you see zero remove the bulb from the socket, set the DMM for DC voltage turn on the ignition switch, set the signal switch for the side of the car you are working on and test for voltage at the pins that connect to the bulb. You should see intermittent voltage if the circuit is good to the signal light. If not, trace the harness back to the connector and switch the DMM to Ohms again and test for continuity of the harness from plug to socket.
One more thought , take the wiring apart where it passes thru the firewall and clean/ reconnect. Sure sounds like a ground problem but wiring can be tricky. Old wires can also break inside the plastic. If the only problem is the front turn signals it might be in the collumn. Good luck
Yes, the dash indicators do blink and I can hear the flasher unit working. The bulbs are brand new. And will only go into the socket one way. The sockets are surprisingly clean and not corroded at all. I'm not getting any flasher signal to the harness at all. I used the DMM to test the contacts at the bulkhead connector at the firewall and all those results matched what I was seeing at the lights themselves. What's strange is just last night I was able to drive the car a bit and returned home right at dark. When I backed it in the garage I was able to see the rear lights on the wall. All lights worked when asked to do one thing at a time. When I turned one flasher on and stepped on the brakes at the same time the flasher would stop. I would try this for both sides and after two times the rears started working like they should. All I did was keep moving various switches (turn, brake, tail) and they started working. I tell ya, every time I start the car I have a different set of lights that work but it's almost never the same ones. I have seen the front lights flash a few days ago but nothing since. It's just standard 1157 yellow bulbs in the front isn't it? Thanks for all the input, appreciated! :beer
You were replying while I wrote my last post, thanks. The steering column is where I am headed next. Gotta love 44 year old tilt columns and the wiring inside them! uzzled:
Not quite sure what you mean by the results were the same as at the lights. Try removing the parking light bulbs and test for voltage at the contact points in the sockets to the ground side of the socket. That will tell you if the harness is good to that point. As far as the turn signal switch and wiring in the steering column. On my '64 Electra the signal wiring is at the lower end of the column and operates from a slide wire from the signal stalk. There is no wiring in the column. That could be different in the case of a later model.
I would get 12 volts at the individual pins (at the firewall) as expected. When the parking lights (only) were on, the correct pins were energized that would turn the parking lights on. When I turned the headlights on the pins that energized the headlights would show 12 volts and the pins for the parking lights would go to zero volts. All of this is as expected, that's all. Until I get the pins to energize at the firewall there's not much sense in digging deeper into the wiring harness or sockets. It may be a day or two before I can do anymore, it's snowing right now and I have to go plow. ou:
After much grief, the turn signal switch is BAD. On the wire loom connector the front left and front right wires are the ones furthest to either side of the switch (if that makes sense). At first I thought the cable wasn't adjusted right and wasn't fully moving the switch so I just took the cable off and moved the switch fully with my finger. The flashers blinked twice and never worked again in any position. This stands to reason since I've had to replace almost all the switches under the dash anyways. At least this seems hopeful! Thanks for all the input, it'll be a while but I'll post up the results when it's back together.
