Electrical Turn Signal Gremlins

[USSprinter]

I am currently carrying out a “refurbishment” of a 1974 Sprint that sat under a cover for six years (the current “PFJ” postings on the Restorations thread are tracking that). I have now run up on a problem that may be of a more general Dolomite issue, so I am posting some questions on that topic here in the Dolomite-related thread.

I stumbled on this problem during the course of doing functional tests on all the electrically related controls. All the controls responded normally until I got to the emergency flashers and the left turn signal function. That is when I observed the following strangeness:

1. When the emergency flashers are turned on, all four flashing lights functional normally, but the horn also blows rhythmically in sync with the flashing lights. At least that verifies all the exterior turn signal bulbs front and rear are operational, but is the horn supposed to also be blowing in sync with the indicators? That seems weird.
2. When I flip the turn signal stalk for a right turn, the signal lights on the right side (front and rear) flash normally. But when I do the same for a left turn, the left signal lights do not flash front or rear (even though they were flashing in Step 1), AND the horn emits a faint, rapid bleeping noise at the same time that the stalk is positioned for a left turn.
3. When I push in the horn stalk, the horn does not sound. Note that this is a newly replaced horn/flasher/turn signal stalk unit. With the old stalk unit, the horn did sound,

I am at a loss as to what to check next. All the other controls seem to be operating normally. I would greatly appreciate anyone's suggestions. Perhaps my problem is not unique?

Thanks!
Mike

[xvivalve]

1. No
2. The hazards and indicators run on separate circuits, though some of the wiring is common
3. The end of the stalk will pop off allowing you access to the horn contacts to test them, however as it is related to the left front indicator I would check the earth on the back of that. You can test with the old switch just by plugging it in under the dash to see if the horn still works with that and if it does it kind of eliminates what you've done from being the cause of the problem. Whilst your new column switch is new, it is an aftermarket copy and you'd be unwise to assume it is faultless! I'd also look at the earth for the horns...

[USSprinter]

1. No
2. The hazards and indicators run on separate circuits, though some of the wiring is common
3. The end of the stalk will pop off allowing you access to the horn contacts to test them, however as it is related to the left front indicator I would check the earth on the back of that. You can test with the old switch just by plugging it in under the dash to see if the horn still works with that and if it does it kind of eliminates what you've done from being the cause of the problem. Whilst your new column switch is new, it is an aftermarket copy and you'd be unwise to assume it is faultless! I'd also look at the earth for the horns...

Thank you for the rapid response and helpful suggestions. I had a passing thought: this is for an early Sprint (1974), and the new column switch I received was the part #218498, which is what is now generally available. Any chance that there was some subtle difference that I did not notice between column switches for early and later Sprints? What I received *seemed* to look identical to my old switch. I have studied the wiring diagrams and can't see how my hazard switch could activate the horns - some sneak circuit? As suggested I will retreat to the old switch to test the horn, and check both earths. Thanks!

[Carledo]

I'd check VERY carefully that the wiring colour codes on the plug on the new switch actually match those on the socket in the car's loom. It would be easy for someone in a Chinese factory to get it wrong somewhere. With 7 wires, the possibilities for error are excellent!

At least you have the tool to swap the pins in the plug round if need be!

PS, IIRC there is actually ONE wire that doesn't colour match across that plug, again from memory, it's black on the switch side and purple or purple/black on the body side. I'll check tomorrow when there's some daylight and get back to you with definitive info. Maybe a pin-out diagram if I can draw something legible!

As a bit of help in the meantime, the colour codes are:-

Green/Red........Left indicator
Green/white......Right indicator
Blue/Red...........Dip beam
Blue/White........Main beam
Purple..............Fused permanent live for horn and headlamp flash facility
Black................Lead out to horn (this is the one that is purple/black on the other side of the connector block)
Light green/brown.. Indicator power in.

As far as i'm aware, the Sprint is the only Dolomite model that doesn't have an "early" or "late" indicator switch. The difference is in the plug, early models (that AREN'T Sprints) have a grey moulded rubber plug that the pins can't be removed from and later cars have the Lucas/Rists plug that you have fitted. All Sprints have the Rists plug.

You can see from the above, that if the black was swapped for the green/red in the plug you'd get exactly the condition you describe. The confusion where the hazard switch illuminates all 4 flashers is because it has a separate switch and flasher unit connected to all 4 lights and the horn is running off feedback.

Steve

[USSprinter]

OK, in groping around under the dash with a strong light, I found at least the source of one problem (the horn button on the new stalk does not blow the horn). As I was inserting the new plug into the main harness plug, I did not realize that one of the male pins in the new plug simply pushed its female connector in the existing main harness plug out of the plastic body of the main harness plug. So that male pin was not connected to anything after the two plugs were joined. I just didn't see that outcome since it is impossible to see much in the darkness under the dash. And that male pin was for a purple/black wire, which is......the horn wire. So no horn. Good grief.

So NOW the question is how do I reinsert that loose female connector back into the plastic body of the main plug? My Terminal Removal Tool serves only to extract the male pins from the plug. Is there an analogous tool (a Terminal Insertion Tool?) used to insert the female connectors into the plug? That seems to be physically impossible, but that female end of the harness must have been assembled somehow???? Double good grief.

Steve - I just saw your detailed explanation after I wrote the above. THANKS!! I will be digesting your details in the morning when I can see straight again. I sure hope it is a case that that our mutual Chinese friend just swapped some wires in assembling the new plug. It would also have helped if I was not so dense that I did not realize that I had dislodged a female connector in mating the plugs. My excuse is that I am on my 78th Orbit of the Sun and don't see that well under dark dashes that I can hardly crawl into. This is a tough hobby!
Mike

[USSprinter]

I have checked the color coding on the wiring on both sides of the harness plugs, and they do match. I have 8 wiring connectors on the harness. In no particular order, they are:
1. Green/red
2. Purple
3. Blue/red
4. Green/white
5. Black
6. Green/brown
7. Purple/black
8. Blue/white

At least I now understand that the column stalk and the emergency flashers operate the indicators independently. Still trying to figure out how to re-insert that loose female connector back into the plastic plug body…….

[soe8m]

Bend back the tabs out that your tool bend in.

Jeroen

[USSprinter]

Bend back the tabs out that your tool bend in.

Jeroen

Ahhh. Just to understand, first I bend in the lock tabs (which makes the female connector’s body “slimmer”), then I pass the connector through the hole in the plastic harness plug body until it fully sticks out the other side, then I bend out the lock tabs to their original protruding position, and finally I pull the female connector back into the harness plug where the the lock tabs now hold the female connector in place awaiting the insertion of the male pin in the plug on the stalk harness. I am now heading back out to the garage where this fix will hopefully take less time than typing all these werdz.
Thanks!
-Mike

[soe8m]

No, just bend the tabs to the original position and push in the terminal in the plastic housing from behind.

Jeroen

[Carledo]

Here is my approximation of a "pin-out" diagram for the plug and socket!




The double purple in the loom socket marked 4, the second (smaller!) wire loops across to P8 and powers the headlamp flasher.

The larger purple lead at P4 powers the horn switch, this is the one that changes from purple in the socket to black in the switch's loom. Black is power IN to the horn switch.

My theory is that the pins at P1 and P2 (green/red and purple/black) have been reversed. The test will be that,if i'm right, pressing the horn will light the nearside indicators, they won't flash, just stay on while the horn switch is pressed.

I've taken this from a 78 series3 Sprint loom as I don't have a series 1 loom where I can see it. But the wiring diagram in my shop manual insists they are both the same.

Hope this helps, Steve

[USSprinter]

Steve,

Thank you so much for taking the time to make the pin-out sketches. They helped to confirm for me that on both sides of the harness plugs, my color-coded wires were pinned at all the exact same locations as in your diagram. In particular, there was no fab error in the new turn stalk harness wiring, no reversal of P1 and P2. So I needlessly slandered our mutual Chinese friend.

Now this is where things get positively (or negatively?) weird. Ten minutes ago (now confident that my pin wiring was all correct), I went out, crawled into the driver's footwell, and "forced" the previously disconnected (but not previously spotted by me) female purple/black connector in the main harness plug to mate with the purple/black male connector in the turn indicator stalk harness. This of course is the connector to the horn button. After I did that, everything was back to NORMAL.

When I pushed the horn button, the horn blew. When I clicked the turn indicator lever left or right, the correct side's turn indicators started flashing. When I pushed in the emergency flasher, all four flasher bulbs started flashing, and for the first time, the horns did not blow in synch with the emergency flashing (adios Admiral Hornblower). So all my bizarre behaviors were simply due to that ONE horn-related non-connection (the purple/black wire) across the two harness plugs.

Now my fundamental problem still exists: the female purple/black connector is not properly "locked" into the main harness plug. To achieve the above results, I "forced" the connection to mate by holding that female connector in place within its plug while I offered up the other plug. The tight fit between the pin and the female connector is ALL that is holding the latter in place within her plug. There were no locking tabs on the female connector as in Jeroen's photo. The connector only had a longitudinal split in its body, so all I can see to lock the connector in place is to widen the gap of that split after the connector is fully inserted into the plug. I can't see any remedy. In the future, when the horn ceases to blow, I will know that the connection has just come apart again.

I suspect that this particular connector was already loose a long time ago. When I disturbed it by inserting the replacement turn indicator stalk harness plug into the main harness plug (which just pushed that connector out of the plug, leaving it hanging loose), the horn circuit became disconnected.

I don't claim to understand Dolomite electronics. Just disconnect the horn button output, and the left turn signals go away, and the emergency flashers also blow the horns rhythmically. Wha??

At least everything is back to NORMAL (for the time being).

[soe8m]

There's alway's a tab to hold the terminal in the housing.

Jeroen

[dursley92]

Look at Jeroen's picture and you can see two little tags sticking out near the bottom. Both the male and female connectors use those to locate them in the plastic plugs. If the connectors have been taken out or disturbed you will need to re-set them so they stick out slightly like in the picture. Then when you push them back into the plastic plugs they "click" into position and are locked in place.

[xvivalve]

There's alway's a tab to hold the terminal in the housing.

Jeroen

Until it fatigues and drops off...