'71 Vixen Electric Schematic?

'71 Vixen Electric Schematic?

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CapRic

Original Poster:

11 posts

76 months

Friday 1st December 2017
quotequote all
I'm looking for better info on the electrical wiring on my '71 Vixen 2500. Specifically, the simple horn circuit, but an entire wiring schematic might be nice for future use on other issues! Does anyone have this, or anything close? I've been using Dan Masters' TRiumph TR250-TR6 book, as a general guide, but it really doesn't line up with my Vixen.
Otherwise, anyone with a car similar enough to mine that might be able to give me some hints?
Issue right now is no power to either of the horns ...but there *was*, a few days ago before I started troubleshooting with alligator clips & leads confused did I fry something?
I always had power to the horns. I just needed to sort the grounding through the horn button & steering column. But now I don't have power to either of the horns' + side terminals.
Presently, there's a Green/Brown wire to the + terminals, which used to carry power. I can't seem to trace it back thru the wire bundle. Where do the horns get power? The only "hot" (un-switched with the key) fuse "box" with *one* fuse, (firewall, farthest right on the passenger side) doesn't seem to power anything (wires lead to the fuse, but no wires exiting).
Anyone with any 70's era knowledge on how this was wired, or having a source for a schematic?
Thanks!
Rick


Dollyman1850

6,316 posts

249 months

Andrew Gray

4,969 posts

148 months

Friday 1st December 2017
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Well the Horn is permanent Live if that is a help and the horn switch is earth maybe that will help
Andrew

Astacus

3,363 posts

233 months

Friday 1st December 2017
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This the wiring diagram for an early Vixen S2 (not, I think a 2500 though)


CapRic

Original Poster:

11 posts

76 months

Saturday 2nd December 2017
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Many thanks for the last two schematics provided (the link & the photo), as well as schematics that TCTVR emailed to me this morning.

I've been straining with a magnifying glass here, but at least what I'm seeing looks familiar (correct wire colors, etc.).

I've discovered that I've also lost my hazard flashers (but all my marker lights, signals, tail lights are OK. So, maybe I just lost the control circuit to the hazard switch or flasher unit?).

I'm tracing that Brown/Green (N/G) wire back from the (+) terminals of the horns to figure out where they get power from. Yes, it used to be continuously "hot", but it's dead now. irked

On paper, I trace it back to a wire connector, which is fed by a Brown/Blue (N/U) wire which, prior to a *FUSE* is a solid Brown wire from the starter solenoid). Ah-HA! **I'll have to look for that fuse**

I do see the Brown wire coming from the starter solenoid & going into the wrapped wiring harness. And I do see a Brown/Blue wire up at a fuse holder on my firewall. (Thing is, the "fused" side of that "hot" fuse holder has *no* wires on it. That fuse, which is good, serves no purpose.)

But, according to the schematic, there's an inline fuse where the wire *changes* from Brown to Brown/Blue. That would be in the wrapped harness somewhere!! Who puts a fuse in the wrapped wiring harness? Also, the *line connector* where the Brown/Green wire goes from that connector to the horns.... apparently that's somewhere in the wrapped wire harness too!

Does anyone with a car close to mine (1971 ....round tube chassis, 2.5L six ....never had electrical "upgraded"), have anything more than 3 fuses over on the passenger side of the firewall? Any chance there might be a fuse or two under the dash somewhere? (that's where the wire bundle leads).

Still digging here. Any suggestions appreciated!

Thanks!

Rick

Dollyman1850

6,316 posts

249 months

Saturday 2nd December 2017
quotequote all
Check the link wire on the column.. there is a flexible coupling which has a bridge wire and this can often be the cause of an inoperative horn.
N.

Andrew Gray

4,969 posts

148 months

Saturday 2nd December 2017
quotequote all
Dollyman1850 said:
Check the link wire on the column.. there is a flexible coupling which has a bridge wire and this can often be the cause of an inoperative horn.
N.
Yes that can fail however that is an earth bridge wire Neil so if there is no live feed at the horn that would not be the cause.
As for cars that are on the road with totally original wiring? not many i would have thought most will of been upgraded somewhat from original.
Andrew

johnh8

62 posts

111 months

Saturday 2nd December 2017
quotequote all
I have an early 3000m with an original wiring harness which is vixen in origin. If you look under the dash on the drivers side in the harness you will find a triple bullet type connector the supply to this is via an inline fuse which may be on the bulk head or under the dash. This connector feeds the horn, hazard switch,cigar lighter and interior light, well it does on my car yours may be different it is a TVR after all.
Hope you find this helpful.

John

CapRic

Original Poster:

11 posts

76 months

Sunday 3rd December 2017
quotequote all
John, I'll look into that possibility. Thanks.
That would mean that the Brown wire off of the starter solenoid (+) POS, joins the wiring harness which goes toward the firewall (which it *does*) & then
thru the firewall (?), *then* to the inline fuse, & then the line connector for the wires to all the components you mentioned (including the horns fed by a Green/Brown wire). If that's the case, then that wire would run back out to the horns & then back to under the dash (to the steering wheel horn button, where it ends at GND via the grounded steering column). This all corresponds with the wiring schematics that I have. But the schematics don't show where the firewall is. I would have thought that the inline fuse & line connector would be on the *engine side* of the firewall (but, maybe not). Maybe the "fusing" & "branching" of the main power (Brown) wire all takes place under the dash? I'll have to dig some more to find out.

CapRic

Original Poster:

11 posts

76 months

Saturday 9th December 2017
quotequote all
That was exactly the case! The power for the horns/hazards/cigar lighter comes from the starter solenoid, goes to *under the dash*, then through an inline fuse, then to a wire connector for all those components..... and then the horn wire goes *back out front* to the horns before *returning* to under the dash to the column & the steering wheel horn button!

I replaced the fuse & fuse holder & I'm in business again with power (hot POS) to the horns!

Actual horn operation problem, however, is in the grounding of the steering column. I thought I had ruled that out weeks ago when I attached a heavy jumper cable between the actual metal steering shaft right to the battery NEG (& the horns still didn't work)!

Anyway, a 16 gauge test lead from the steering shaft to the frame results in proper horn operation from the steering wheel.

So, I know that the steering shaft is of two sections & there's a ground wire that connects those two sections.
But, ......the *final grounding* is simply through the greasy & moving contact points of the steering shaft to the steering rack?!? How is that possible?

Penelope Stoppedit

11,209 posts

108 months

Saturday 9th December 2017
quotequote all
There should be an earth return bolted to the steering column mounting inside the vehicle rather than relying on a possible good earth at the steering rack

CapRic

Original Poster:

11 posts

76 months

Monday 11th December 2017
quotequote all
Penelope Stoppedit said:
There should be an earth return bolted to the steering column mounting inside the vehicle rather than relying on a possible good earth at the steering rack
Thanks. I'll look for that. So GND is then established thru the steeering column mounting inside the cabin ...from the steering wheel hub ...via the bearing that supports the steering shaft &/or steering wheel hub?
What then is the purpose of a wire bridging the two sections of the steering shaft under the bonnet? (I thought that was to carry the GND to the end of the shaft ...for contact with the steering rack & earth).

tomtrout

595 posts

162 months

Monday 11th December 2017
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Correct. I have no extra earth connection on my Vixen. Does not solve your lack of volts at the horn/s.

GTRene

16,369 posts

223 months

Tuesday 12th December 2017
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I have one from a Vixen S2 and a Vixen and a 2500 M but do not know if that is a vixen 2500 or a 2500m M-series.

this one just says Vixen


this one vixen s2


and this one 2500 M

CapRic

Original Poster:

11 posts

76 months

Tuesday 12th December 2017
quotequote all
tomtrout said:
Correct. I have no extra earth connection on my Vixen. Does not solve your lack of volts at the horn/s.
Solved the "no volts" problem by finding the fuse under the dash (see my post about 3 above this).

My '71 Vixen 2500 has, at the very forward end of the steering shaft, a coupling to a "lower" (short) steering shaft ....and across that coupling, a small ground wire to provide a circuit path to the lower part of the steering shaft (because I believe there's a rubber piece between the two sections). So that brings the ground circuit to the end of the steering shaft & I think the shaft then completes the ground through the steering rack assembly. But I'm questioning how good of a ground can be achieved through a bearing & pinion gear contact to the steering rack assembly.

Thanks for all the schematics. These will be good to file away for future use! Much appreciated.

Schematics, of course, only show that the ground is made with the horn button depressed. Doesn't show the non-wired path thru the mechanicals to earth.


Edited by CapRic on Wednesday 13th December 22:34