Underhood light: where does it go?

7173Mustangs.com

Help Support 7173Mustangs.com:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Joined
Jun 14, 2019
Messages
551
Reaction score
164
Location
Coachella Valley (Palm Springs)
My Car
1973 Convertible, 351 4v CJ, C6, Mach 1 Decor options, power: steering, brakes and windows, a/c, Rally Pac gauges, Deluxe interior.
[url=https://ibb.co/ZVjjKXW][img]https://i.ibb.co/zrMMbxG/s-l1600-2.jpg[/img][/url]
My underhood light is just a fixture with a wire that goes nowhere. The wire ends about 18" from the fixture as a ragged end and attaches to nothing. Yes, I have a wiring diagram, and I can trace the BK-Y-D wire easily, but underhood, where does it join the wiring? I have searched and searched for a dangling unattached underhood BK-Y-D wire unused with a raw end to no luck at all.

I guess I'm wondering if anyone can tell me about where, or what recognizable other wire/cable/hose is near where the light should connect to the harness. Karma points if you include a usable photo.
 
You need to have the convenience group harness in order to use the underhood lamp. The lamp has a bullet connector on the end of the lead that connects to a socket on the convenience group power lead (black with yellow dot). This power lead is routed along the top of the passenger side shock tower brace. Look for the socket dangling from this power lead near the firewall.
 
Being a convertible, the harness Mike is talking about will be present, as it provides power for the convertible top pump motor. See pic below for the female bullet location.


View attachment 59383

If it were just looking for a bullet-plug that isn't plugged in, that would be easy. I have the bullet plug and a raw wire. I need to know where the plug shown in your photo joins the harness. The wire ending in a raw end is hanging down from the light itself.

(I took another look. The big lump shown right at the edge of the brace seems it might take an additional wire. I can't see from Hemikiller's photo whether the bullet plug he has circled actually joins the harness at the same big lump thing)
Missing feed.jpg
 
Last edited:
Easy enough to find, just about anything you can think of has been covered in this forum. Here are two examples of what I found by searching the forum:
https://7173mustangs.com/threads/under-the-hood-light.31261/#comment-321176https://7173mustangs.com/threads/under-hood-light-convenience-group.30842/

Those are good for understanding mercury switches and how to install and route the light, but go no further than up to where you plug it in. I have the convenience group. I have the lamp. I have both sides of the bullet plug, I just need to find where it goes. There might be something in the first post's link, but the link to an old thread is "Oops, not found".
 
Those are good for understanding mercury switches and how to install and route the light, but go no further than up to where you plug it in. I have the convenience group. I have the lamp. I have both sides of the bullet plug, I just need to find where it goes. There might be something in the first post's link, but the link to an old thread is "Oops, not found".
The second link (above) is the updated link for the one you couldn't access in the first link.
The '71 wiring diagram shows it the clearest, runs from the bullet connector through a 7.5 amp fuse to the battery terminal on the starter solenoid. There should be another B/Y-D wire connected to the battery terminal that runs to the interior. The routing for the engine compartment light is along the top of the right (passenger) side cowl/shock tower brace.
 
The second link (above) is the updated link for the one you couldn't access in the first link.
The '71 wiring diagram shows it the clearest, runs from the bullet connector through a 7.5 amp fuse to the battery terminal on the starter solenoid. There should be another B/Y-D wire connected to the battery terminal that runs to the interior. The routing for the engine compartment light is along the top of the right (passenger) side cowl/shock tower brace.
If you scroll up to Hemikiller's photo, are you saying there is only one wire running along the brace and the underhood light plugs into that? (his empty plug would be connected to the one wire you see)

That wire does run to the solenoid. One of the plastic lumps looks as if it could take a wire. In my photo, the plastic lump that could take a wire is just past the edge of the brace.
 
The one wire from the lamp is for the +12v. and that goes to the solenoid. The lamp gets its ground connection from getting fastened to the hood. 2 wires from the lamp are not needed.
As I recall when I replaced my underhood light, the wire from the light didnt really join into any harness. It more or less ran parallel to other wires so it wasnt an issue removing it to replace.
 
Last edited:
The original convenience group harness just has a female bullet connector socket with a short lead spliced into the black/yellow dot accessory lead that runs from a circuit breaker on the starter solenoid and then along the brace. If you don't have the male or female bullet connectors and you just want it to work - just splice into the black/yellow dot accessory wire and use whatever connector you want. If you have a lead you think might be the splice, you can check it with an ohm meter - measure the resistance from the wire to the circuit breaker.

There are a couple of different options on that accessory lead. For convertibles or cars with heated rear windows without the convenience group, the lead runs from a circuit breaker on the starter solenoid to a 3 port connector under the dash, and the lead does not have the spliced in bullet connector under the hood. For power window cars without the convenience group, the lead runs from a circuit breaker on the starter solenoid (or a separate terminal if the car has a lot of options) to a relay on the driver's side shock tower and then on under the dash to the power window harness, again without the bullet connector for the underhood lamp. Convenience group car harnesses differ because they have that splice.
 
The bullet connector is spliced into the harness at the "lump" just off the brace in your photo. Yours has broken off, not an uncommon problem. Skim the insulation back and solder it back to the accessory feed wire.

1643466241902.png
 
The bullet connector is spliced into the harness at the "lump" just off the brace in your photo. Yours has broken off, not an uncommon problem. Skim the insulation back and solder it back to the accessory feed wire.

View attachment 59401
Thankya, thankya, thankya. I kept expecting there to be another raw-ended wire for this to connect to so I never really examined the one I have. And upon examination of "the lump", I see now what to do.
 
Back
Top