I’ve been helping a friend who is trying to reassemble an XK140 that was taken apart many years ago. Below is a photo of a female wire socket on the steering column at the interior side of the firewall.
What is the purpose of this socket, and what color wire plugs into it? Thanks!
It is for the horn. I don’t know the color of the wire from memory.
It’s a Blue wire on a 150 that connects to horn relay. You should get a full color wiring diagram for that project. Check out Prosperos Garage. Prosperos@colorwiringdiagrams.com
Bob and Kris, thanks for the help. The horn button assembly is not yet installed, but there is a single wire extending out the hub of the steering wheel which should be part of the horn circuit. I’m wondering if there should be continuity between the wire in the steering wheel hub and the female socket shown in my photo?
The entire wiring harness is new, but it was installed by someone else, There is a black and green wire that isn’t connected to anything. Hopefully, this is the wire that leads from the female socket to the horn relay.
Sorry, but I don’t have a 140 wiring diagram to know the proper colors for 140s. On a 120 the horn contact wire is green as opposed to blue for the 150s. When you depress the horn button, you provide the ground to complete the circuit for the switched hot wire coming from the horn relay.
If your horn relay is installed and there is a black and green wire there, pretty sure it should also be connected to the rotating horn contact in your photo.
Mike, Sorry, I don’t have a wiring diagram handy and my knowledge is really limited to rebuilding the steering column. As Kris said, pushing the horn button completes the circuit by connecting to ground so only one wire is necessary. Yes, there should be continuity between that wire and the female bullet connector. If there is not, you may have to pull it apart and rebuild. The bullet connector is mounted to a copper piece (C8158) which can wear down as it rubs against another copper part (C8152) which rotates with the steering shaft. This can disrupt the circuit. You might get away with just replacing C8158 if the C8152 is in good shape. In my case, they both destroyed each other. The wire running down the shaft can also get disconnected or break from age and the constant rotation of the wheel. The insulation on mine was in bad shape. You generally don’t want the horn sounding randomly on its own. The usuals sell a kit to replace the worn parts, but shop around as I recall that the price varied considerably. SNG Barratt has a good drawing showing all the parts in its kit.
Mike,
See attached XK140 WIRING DIAGRAM, and most importantly the reverse side page detail of switching as on original Wiring DIagram sheets. Most you see are only copies, that copy front side only…
Hopefully my scan is good enough for you to blow up detail.
Roger
On the 140 that connector should have a black wire with a green tracer so you are right about the spare wire. There is no horn relay, the wiring is direct to the horns.
As Bob said, if there is no continuity to the connector the problem is likely to be the slip ring assembly. I have covered the rebuild of this on my website www.stretton.tv/steering.htm
Thanks everyone for the details and description of the XK140 horn circuit. This is exactly what we need.
