Here's the old switch with the wheel removed. It turns out the nasty noises were coming from the horn contact plate. You can see the yellow wire is covered with copper filings.
Here's a closeup off the plate. You can see the inner contact ring is worn through while the outer contact was actually hitting the solder joint. Unfortunately you can't buy just this plate so I had to buy a whole new wheel mounting kit.
This is what I found when I crawled under the dash to disconnect the turn signal switch from the harness. Whoever installed the previous switch didn't bother to reuse the other half of the connector and just pushed the wires in. More than one wire fell right out. This is probably why the dash indicators weren't working. Luckily I was able to find the correct matching connector online.
Here's the new switch in place. I know, looks like the old switch.
Before I took the old switch out I found a wiring diagram online that showed how to wire the two harness connectors, a 6-pin and a 2-pin. Like an idiot I didn't bother matching the old wires to the diagram. To make matters worse, when the new switch arrived it had different colored wires than the old one. I figured I could just compare the two switches and be able map the new wire colors, but when I went back to the diagram, half off the wires on the old switch didn't match. Let the fun begin.
So, I then spent several hours trying to connect the new switch. Some of the wires are hot all the time so I had to be careful not to fry something. Thus, every time I tested the connections I had to disconnect the battery, crawl under the dash to move the wires around, reconnect the battery, climb back in the car to turn the ignition on and flip the turn signal, check the front signals and then the brake lights to see my if I had it right.
I probably had the wiring correct after just a few tries. But no matter what I tried I couldn't get the rear lights to work. So I kept moving the connections around. After a while I got frustrated and decided to take a different approach.
First thing was to look at the wiring diagrams. Right off I noticed that the one of the wires from the switch went to the turn signal flasher and in turn to a terminal on the back of the ignition switch. Then it hit me -- I remembered finding a loose wire on the back of said switch. I didn't tighten it at the time because it's very inaccessible and I was busy with something else at the time. This sounded promising. So I climbed back under the dash and tightened up the connection.
But when I tried the turn signals again, everything worked except the rear lights. So I used a multimeter to check the voltage coming off the switch for the two wires that I thought were for the rear lights. While the turn signal was activated I could see the voltage cycle on and off. Bam. So at least I had the wiring right. Then I went back in the trunk and checked the connection back there. Again, I could see the voltage cycling on and off. I turned on the parking lights and the license plate light, which shares the same wire as the tail lights, came on. However, the tail lights were still dark.
So why don't the lights come on? The tail lights are totally custom and are sealed to the body. I know, who does that? I have power going to the lights but no light. The housings are plastic so maybe the ground is bad. But the only way to see what's going on inside the lights is to cut them off. It's strange that the tail lights stopped working after I took the turn signal switch apart. I don't see how I could have fried something by hooking up the wrong wire. 12 volts is still 12 volts. I'll have to investigate the grounding for the lights, hopefully without removing them.
First thing was to look at the wiring diagrams. Right off I noticed that the one of the wires from the switch went to the turn signal flasher and in turn to a terminal on the back of the ignition switch. Then it hit me -- I remembered finding a loose wire on the back of said switch. I didn't tighten it at the time because it's very inaccessible and I was busy with something else at the time. This sounded promising. So I climbed back under the dash and tightened up the connection.
But when I tried the turn signals again, everything worked except the rear lights. So I used a multimeter to check the voltage coming off the switch for the two wires that I thought were for the rear lights. While the turn signal was activated I could see the voltage cycle on and off. Bam. So at least I had the wiring right. Then I went back in the trunk and checked the connection back there. Again, I could see the voltage cycling on and off. I turned on the parking lights and the license plate light, which shares the same wire as the tail lights, came on. However, the tail lights were still dark.
So why don't the lights come on? The tail lights are totally custom and are sealed to the body. I know, who does that? I have power going to the lights but no light. The housings are plastic so maybe the ground is bad. But the only way to see what's going on inside the lights is to cut them off. It's strange that the tail lights stopped working after I took the turn signal switch apart. I don't see how I could have fried something by hooking up the wrong wire. 12 volts is still 12 volts. I'll have to investigate the grounding for the lights, hopefully without removing them.
Anyway, since the switch appears to be working correctly I buttoned things up a bit. Here's the wheel all cleaned up and back where it belongs.
Third try's a charm. As I said before, the tail lights are solidly sealed to the body. The only wires going into the housings are two sheathed wires.
The white wire (connected to black from the harness) is also tied into the license plate light, which works, so I know that wire is good. The black/red is for the backup lights. One of the sheathed wires carries three conductors. White is for the parking lights and the red and black are for the left and right signals. All three of these test good. The other sheathed wire runs along the left side of the trunk towards the front. I removed the door sill plate to see if it ran through there.
As you can see only two conductors were in this sheath. The black wire is grounded to the sill--so much for that bad ground idea. But what about that red wire? Then it hit me. It must be +12v power. I couldn't figure out how the rear lights could sequence when the turn signal wire was only sending a momentary signal. There must be some kind of "brain" in the rear lights that requires constant power. So I checked the voltage at this splice and got zero volts. That's good. The lights weren't working because they weren't getting power, not because I fried something.
This is where the red wire goes, wedged right into the fuse box. Nice. I had seen this wire before but I assumed it went to the radio or something. It's not even protected by the fuse as it's on the hot side.
Here's the back where you can see the always hot black/yellow feed come in. Not wanting to zap myself, I disconnected the battery so I could check the continuity in the red wire. That's when this happened.
The red wire fell right out of the connector. Bingo! Turned out to be a very simple fix. Just to be safe I wedged the terminal on the other end of the fuse so it would be protected. If you're gonna hack something, at least do it right. I'll look at upgrading this fuse box to something more modern in the future.
And here's the final result result of several wasted hours, all because of a loose terminal. You can see how dim they are, even on an overcast day.
