1951 XK120 FHC Wiring Harness Installation

Starting a new thread as I think my early FHC may be different from the DHC wiring thread of a couple of weeks ago. It also looks different from Tadek’s OTS photos and Bruce Wright’s drawings of his OTS installation he did back in '02.
I’m pulling and pushing in the new under-dash harness. This job must have been hard enough for the factory guys with the body on a trolley, but it gets worse, I’m doing it on a fully assembled car.
There are grommets up in there incidentally where the harness passes through from left to center and center to right. There are bunches of wires protruding from places where the wrapping stops, and I found it easier if I wrap a bit of masking tape around them to gather them together for pushing them through the grommets.
Now comes my first question. The dash panel has 2 single holes and 2 double holes. So through which of these four holes should I pull out the portion of harness that goes to the instrument panel?


I’m also thinking there should be grommets on those holes. Does anyone else have grommets there?

The double cut holes indicates yours is an early car and bulkhead is both roadster and fhc ie the body raised 1 inch on a few of these early fhc cars i have seen they have two sets of brake and clutch pedal holes as well unused set with small patch over it
The rear body deck is a roadster which has been cut out and edge turned up to spot weld roof on.
Basically I see they took an almost complete roadster shell and made a fhc

PS very very early cars ie 679002 the vents for screen were actually mkv vents not the usual xk120 vents

Found it. Viart covers it on page 357. Second hole from the left.

On to the next dilemma.
Viart on page 360 shows three holes behind the wiper motor to the right of the ID plate, one of which is for the big wiring harness going to the bullet block, one for the wiper flex cable and one for the wiper loom. I just have two holes there.

This is my 53 FHC before restoration. It’s a LHD

Thanks Phil. That confirms Viart and that what I did was right.


I also discovered why they changed from double punched holes as I have to oval holes as Phil has. You have to get your hand in there to pull the harness and work it around in there. Maybe they had little girls installing harnesses?

I figured out the wiper loom, I just put it in the same hole with the bullet block harness.

BTW Rhode Island Wiring uses cloth covered wire with all the original type end terminals soldered on, and assumes that your components have all the original type end connection terminals, like ring terminals for the turn signal flasher, so if you have something else like a modern flasher or coil with spades you will have to finagle something.

harnesses made here in western australia come with all correct terminals and also all small single wires!
Thats why we started making them back in 1977 as what was coming from overseas was rubbish
terry
tmcgrath@bigpond.com

RIW sent me all the single wires too, all correct terminals and excellent quality work.
By overseas I assume you mean China and India. I recently got some lights made in China and their bullet connectors were too small, didn’t fit the standard sockets.

I come now to the manette control wires. Four bullet connectors.


How should they be connected?
Is there supposed to be a 5-way rubber connector block mounted to the LH valence somewhere near the horn relay? I don’t find any holes for mounting such a thing.
Or did they use four single connectors?
I checked the SPC and Urs Schmid and Bernard Viart’s books and Tadek’s web site, didn’t find anything.

Found it. Thanks again Tadek!
IMGP7395a
Apparently just hanging loose in there. Can’t see whether it’s a 5-way or 4 singles wrapped in tape. Anybody have any more knowledge here?

There should be a 5 way single and a 5 way double Rob, held by a simple strap bracket.

Yes, I know about those two, in front of the radiator, for the headlight and sidelight wires.
This is a third set of 4 wires for the manette control, ending behind the radiator, by the horn relay.

Just found you had the same question I have. How did you wire it?

IMG_20210818_103547032

I have mine possibly upside-down. But I can at least read the markings… :wink:

Bob K.

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Thanks for that but I don’t have any issue with the horn relay and mine is hooked up the same as yours. My question is how do I hook up the wires from the manette assembly to the wiring harness? The wires on the manette are blue, green, white and brown. The brown is for the horn. So since the wire colors or the manette and harness aren’t the same, how do I hook them up? If I figure it out, I’ll be sure to post it so the next guy doesn’t have this problem. Of course the problem also is that all manetts don’t have the same color wires.

On the DB10 relay, 4 controls the left signals and 8 controls the right signals.

green to A4; blue to 4 green/blue on the DB10 relay; white to 8 green/yellow on the DB10

Thanks, I’ll give that a try today and let you know.

Ok, here’s what I got…from the manette wires - green to green (A4), white to grn/ylw,
Lt grn (or blu)/grn/blu. With this configuration, the TRF light does not come on and when I push the turn lever the turn light s will come on but do not blink. This happens with the original flasher and the new one. Should I suspect the flashers are both bad? Is there a way to test the flashers?

Connect a testing wire to A or A1 or A2 at the voltage regulator (A2 may be easiest if there is nothing already on there), touch it to the dark green wire on the P terminal of the flasher, and see if the TRF bulb works.

Now try that test wire on the X terminal, first taking off the medium green wire, and see if it clicks and the signals work.