1998 Dakota, 4 cylinder. The electrical has been the nemesis of this truck.
Stage 1.
When I bought it, the tail lights worked, along with turn signals. Brake lights didn't work. I changed the brake light switch: Fixed. (Reverse lights not working)

After a few days:

Stage 2. Left tail light, along with left turn signal didn't work, brakes lights stopped working on both sides.
The left FRONT turn signal flashes rapidly, right side works fine.
This happened when I opened up the dash to inspect the combination switch. All I did was to remove it, then reinstall. I also noted in the cabin fuse box, where the turn signal relay connects, the relay is loose. If I move it around, the behavior of the turn signals changes.

So I found that close to the left tail light, the cables were frayed. I spliced and added new cable. Now both tail lights work, but no brake or turn signals on both sides. (Reverse light still not working).

Action I'm taking for now: junkyard run will bring me a new fuse panel, combination switch and headlight switches, along with an array of relays.

Would a bad combination switch mess with the brake lights (since the turn and brake lights is the same)?

Any other ideas?
Thanks!

 

I wish I had a 99 FSM to look up for you. Might try the FSM thread. My 01 will be very different.

Pretty sure reverse lights are direct off the trans. I could be wrong on 99- but I thought that part stayed the same.

brake and turn should be the same side of the bulb I believe, with running lights the other side of the bulb? Makes me wonder if grounding issue.

Here's what my 01 FSM says. Yours is likely different, but might give you a starting point.

Black/Yellow is running lights, same circuit as license plate lights.

Black is ground, common for all rear lamp assemblies.

Dark Green/Red is left turn + brake

Brown/red is right turn + brake

Screen%20Shot%202016-06-05%20at%2015-03.17.59%20PM.png

Screen%20Shot%202016-06-05%20at%2015-03.17.50%20PM.png

Screen%20Shot%202016-06-05%20at%2015-03.18.06%20PM.png

Screen%20Shot%202016-06-05%20at%2015-03.15.01%20PM.png

 

I have extremely limited knowledge of the wiring on these trucks, but on my '01 I had troubles with the left rear turn signal. After doing the obvious I brought it to my local mechanic. He located the problem in a 4 wire connector under the truck that was water filled and showed burning wires. Cut it out, wired everything directly, and problem solved. 15 years of road abuse took its toll.

 

Yes, all of the issues I had were due to frayed cables ,brake, turn and high mount brake light. It took a lot of time and searching, but it just wasn't adding up, since all connectors were good. Then, the multimeter use is where its all at.

Haven't looked at the reverse lights, but I am suspecting the switch on the tranny, it maybe once again, jacked up cables

 

Make sure grounds are all good. Sounds like they are, but you never know.

Pull C326 and C360 connectors apart on the rearmost crossmember. These are the chassis-to-body quick connects, both 4 pin square. Check them for voltage.

Again, yours might differ slightly. These are from the 01+ FSM.

Black/Yellow is running lights, same circuit as license plate lights.

Black is ground, common for all rear lamp assemblies.

Dark Green/Red is left turn + brake

Brown/red is right turn + brake

Violet/Black is reverse lights

Screen%20Shot%202016-06-05%20at%2020-08.23.45%20PM.png

Screen%20Shot%202016-06-05%20at%2020-08.23.31%20PM.png