Help Request: New Harness, new flasher box, new turn signal switch, new brake light switch...

[Mutt Hunter]

...and no brake lights nor turn signals.

I had 20 things electrically wrong yesterday, and today those two things are all that's left to work off. All lights work, all gauges work. I just don't have turn signals nor brake lights.

Voltages at #75 female connectors at brake switch are good. The #57 is properly grounded (thanks, Rick!), and as the subject says, everything else is new, just out of the box.

Any advice appreciated. Stay safe/healthy.

dee

[m3a1]

It sounds like the commonality may be your composite lights and how they're grounded. Each mounting bolt is a separate ground. You didn't say that you definitely had power at the wires going into the composite light kits.

Hope this helps.

Cheers,
TJ

[Fil Bonica]

Other things to investigate are turn signal and main lite switch.
If you need either or both,
I have them NOS.

Fil Bonica

[Mutt Hunter]

I have parking lights at all four corners. Main light switch is brand new and everything else it controls is working. Turn signal switch is brand new. Flasher box is brand new. Harness is new.

Would a loose bolt (and by extension, a ground) at one or more of the four corners cause this?

I've studied the wiring diagram ad nauseum...and replaced with new everything it could be.

Signed,

Stumped Chump In Tampa

[Mutt Hunter]

One other thing...even if one or more of the bolts holding the four corner lights was loose and ground was/is bad, shouldn't the flasher/turn signal switch do "something"...click or something?

[Fil Bonica]

The flashers are electronic so no clickks.

Fil Bonica

[m3a1]

Yes, that is a distinct possibility because each mounting bolt provides a ground for a separate section of the light. It's been a while since I looked in one so I can't say with any certainty which bolt affects what from memory. Simplest way to figure your problem out is to check your power leads to the light itself. If it's good at the wire, but certain lights aren't working...it's the light kit....or the ground for the light kit.

Cheers,
TJ

[Mark]

Wouldn't using a test light probe to touch the bulb contact in socket tell you if the power circuit is working?If it isn't then back check to see where you have power

[m3a1]

If I understand your comment correctly, that won't tell you anything if your ground is bad through the composite light assembly. I would be checking for power through the wire to a good ground point on the frame, or straight back to the battery if you have a wire or jumper that will reach that far. In other words, if you can hook up to the terminus of your wires and you have power there, then the only thing left is the light assembly and it's ground points.

[Mutt Hunter]

Update: I think i came up with culprit on the turn signals. Using the series of tests from the circa 1971 -20 manual (thanks again, Rick--the 1982 manual sucks by comparison), i found that i didn't have continuity between the flasher cable connector's A and B and turn signal switch cable's connectors F and H. I went looking for the continuity once i didn't see up/down voltage at any of the lights when the signal switch was activated.





A and B connect directly to the light switch via the large circular connector on back of the light switch...and then via the harness to the four corner lights.

So, with a failed continuity check between the flasher unit and the turn signal switch, here's the question: How does a guy go find where the harness is bad? It could be bad connections with A and B pins inside the flasher cable connector, a short between the flasher connector and the main light switch, some other short on the other side of the new light switch, or some issue within the barrel connector connecting the harness to the turn signal switch.

Any ideas?

Question #2: based on study of wiring diagram, if i find this continuity problem, is this going to fix the brake light issue since I've got power to all four corners and working parking/blackout lights?

dee

[rickf]

Good detective work. I will look over the diagrams in a little while after I get some things done around the house. To answer you second question, yes this should get everything up and running. You say it all goes through the plug, try taking the plug apart and looking in to see if you can see if the pins look like they are in there. It is entirely possible that a pin may not have been pushed all the way in and when you put the plug in it pushed the pin back out.

[D Pizzoferrato]

Rick's response jogged my memory. When I built my A2 with a new body and all NOS parts, I seem to recall an issue that I resolved by studying the plug on the new harness that goes to the Turn signal control. As I recall, these harnesses were made by Unicor. One of the pins was opposite of where it needed to be. Once I determined that. it was a simple matter to disassemble the connector, push the pin out and reinsert it 180 degrees from where it was. The illustrations of these plugs can be confusing as you need to focus on which end of the connector the schematic is referring to.

[Mutt Hunter]

Good news, gents. After a ton of troubleshooting, a confirmed problem with continuity between the flasher and the main light switch in the front wiring harness, and more shorts than i could count in a dry-rotten rear harness, i punted and decided to just replace all the wiring--front and rear.

It took me a few hours to get the new harnesses pulled and to get everything connected, but all lights, gauges, turn signals, brake lights now work.

Next move: replacing wheel bearings and bleeding new brakes. Thanks for all your help with troubleshooting the electrical stuff!

Lesson learned #1: Spend $30 on a good, multi-function multimeter before you tackle the electrical stuff. Had i done that early, i would have saved myself 10 days worth of head-scratching, frustrating trial and error.

Lesson learned #2: Spend $10 on the circa 1971 hard copy version of the -20 manual. Way, way, way better troubleshooting processes and illustrations than the versions from the 80's

dee

[rickf]

[Fil Bonica]

Ah yes !
We all learn by our mistakes!

Fil Bonica