Taillights on Wagonmaster question

W

WagnMastr

Member
I've got a '73 wagonmaster 1010 that has an olds rocket 455 in it, so the wiring has been modified somewhat. It hadn't for 15+ years until just recently. All that is left is a few wiring issues (I hope) for now.
Problem - when I have headlight switch fully on, only the left upper taillight is on, not the right. When I turn on the left turn signal, it doesn't blink. When I turn on the right signal, the right now flashes when previously it was not on.
I get the same behavior whether the headlights are on/off. Front turn signals operate properrly, as do headlights, including high/low.
Fyi, at some point, a po put in a toggle switch that turns on the two lower taillights and that works both on/off.
Also, the left/right blinker lights on the speedo do not work, even though I switched them with new sockets and bulbs, though all other gauge lights do function.
Front side markers work, rear ones did just recently, but now don't, so that May help with troubleshooting.
Any idea where to go to hunt down maybe a ground issue?
 
The light "buckets" for the rear systems self-ground.

Pull the buckets out and clean the contact points, better yet, run a jumper from each light bucket to ground that is clean!

This is by far the most common light-related issue on any of this junkiron! That green weenie t'all ya snaked from skip had the same problems, that was related to the re-paint job that had been done and the light buckets were not making aground contact, we had to rework all the light once we got the rig back to san antone.

Regarding the signal indicators in the instrument pod, ya sure the printed circuit strips are not "open" at some point and all contacts are clean? Also, the pins where the harness connectors plug in are terrible regarding deterioration and become loose in their connection with the circuit boards.

Those crappy multi-point black rubber gang connectors on the rear lighting harnesses also are prolly corroded internally or one or more of the male bullets is partially pulled out of the female receptacle. So ya can eliminate those crap gang connectors and wire each one with a male/female disconnect if ya think ya May ever wanna remove 'em.

Sparky (aka bryce) fought this one entire Sunday here at binder u. A few weeks ago, every time he'd touch a connector it would fall apart and be full of mud/corrosion/spider nests.
 
As always, michael, you are a font of knowledge. Thanks for your insightful tidibits. I will definitely pore through each of those over the weekend. I like the idea of grounding each bucket and switching out the gang harnesses with m/f connectors. That is easy enough for me to do in well under an hour.
I am so close to getting this wm registered, it's killing me!
I have seen the blinkers on the speedo work on some occasions, don't know when they stopped, but probably around the time I put in new bulbs and sockets.:icon_wink:
 
So, I grounded the passenger side buckets, checked the pins in the instrument cluster, checked over the circuit board, checked out and cleaned the gang connectors (which were actally very clean already) and still the same issue on the right upper bucket.
The good,
1. The right turn signal works.
2. The hazards work on the right side.
3. The right side works when brakes are applied.
And, the bad,
4. The right upper light doesn't work in the headlight on or running light on positions. The right rear side marker is not working in those positions, either.

This is kicking my butt! Any further thoughts?
 
wagnmastr said:
so, I grounded the passenger side buckets, checked the pins in the instrument cluster, checked over the circuit board, checked out and cleaned the gang connectors (which were actally very clean already) and still the same issue on the right upper bucket.
The good,
1. The right turn signal works.
2. The hazards work on the right side.
3. The right side works when brakes are applied.
And, the bad,
4. The right upper light doesn't work in the headlight on or running light on positions. The right rear side marker is not working in those positions, either.

This is kicking my butt! Any further thoughts?
Click to expand...

No shit!!!!

And...your recent acquisition is kickin' my electrical butt this morning also! I got some of the stuff fired off that needed fixxin', but the turn signals are still scruuee. More to come about that later.

For the wm:

side markers...pull each side marker bucket out and use a test light with probe to look for current in the wire when the parking lamps are turned on. Test the contact inside the pigtail first, then test the actual wire by probing through the insulation. Most likely the actual pigtail is ng and is easily replaced with a repair part. The generic repair pigtail for the side markers are the ones marked "Ford/GM" at the auto supply. I'm doing the same thing right now on the myrtle creek rig! Every pigtail/socket in the exterior lighting is packed with mud and crap.

The two bulkhead connectors to the driver side of the steering column in the engine bay are the lighting feeds (you already know this!), so use the probe on your test light and "back-probe" and see if each circuit at that point is ok. If so, then the issue is in the wire runs or the socket/pigtails themselves.

There are wire runs down each side of the rear frame rail for the lighting apparatus for the tail light assemblies. So do the same back there, any "plug-in" connection is suspect...simply pull apart, clean and re-connect and see what happens. Use yoyr test light at each "hot" wire connection to check for current. If you have current, then the problem is most likely in the light assembly/pigtails themselves.

Your bullet point #4 I don't understand. When you say "upper" right light"...do you mean the upper tailight unit on the passenger side? Again...trace each wire back into the harness where it plugs into the main run and look for current with the test light at that point.

Working out turn signals and brake lights is very difficult since they share wire runs. All bulbs need to be exactly the same "number" (wattage), the flasher needs to be fresh (they will work on one side and not the other), and they will "backfeed" looking for an alternate ground path and create a false flash that is very weak.

Then...if the problems don't jump right out at ya...give it up for awhile and go play with the kids...it'll still be there when it's kidnap time!
 
Sorry, when I mentioned upper right, I was referring to the light socket in the upper right rear bucket (that works as brake, running light, turn signal and hazard). What is hard for me to figure out, is that if it has current for 3 of 4 of those features, why it wouldn't have current for the running light? I would think the flashers are fine since the all 4 lights function (front and rear, left and right) as turn signals and when the hazard knob is used.

One thing to note - the po had rigged a switch on the dash that operates the reverse lights in the lower buckets. I swapped that wire to the lower bucket with the one that goes to upper bucket/side marker, and both the running light and side marker lit right up! I am using new 1157 bulbs in the rear and 194 for the side markers, per the owner's manual.

I would think that if I got constant power to the top bucket when the running lights or headlights are on, that would do it.

I will keep plugging away (no pun intended), as time permits and let you know when I hit on it.
 
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The turn signals use a different flasher unit from what operates the four way flashers. So there are two flashers units on each vehicle (equipped with four ways).

Part of what is wrong with the turn signals on the myrtle creek rig is...the actual flasher for the turn signals is missing!

Typical wiring for a four way flasher system is to think of it exactly the same as a turn signal system, but a second system is wired to the the stop/turn pigtails in parallel. And if any one of the actual bulbs (typically a dual filament like an 1157 has a poor ground or high resistance ground caused by corrosion in the socket base/bulb interface, then the current seeks an alternative path to ground thorough the other circuit (which is seen as a dim or weak bulk illumination and a very slow flashing if it flashes at all).
 
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