Head Light replacement 1982 Bird

[Dave 82 Heritage]

Need to know how to hold the headlight door open to replace the head light? Any help appreciated!

Dave

[Alan H. Tast]

First things first - do you have a copy of the Owner's Manual? If so, have you looked into it for any instructions? Not trying to be a smart-aleck, but I would think it has something in there about headlight door operation and operation of a by-pass valve to allow the doors to open (the 1980 one does - see post further down). Rotate the by-pass valve to 'vent' the vacuum from the headlight door motors, then disconnect the battery to kill power to the car. Then remove the retaining ring from the headlight housing, pull the bulb, replace with a new one, reinstall the ring, rotate the by-pass valve back to its original position, hook the battery back up and check that everything works.

Regretfully I do not have shop manuals for this generation in my library to look for this specific item, but the '77-'79 T-birds and Lincoln Mark Vs used a similar system that relied on vacuum motors, a vacuum bypass switch and a vacuum reservoir. Typically, vacuum holds the doors closed, and when vacuum is lost they spring open (Most post-'60s cars with headlight doors had a mechanical spring inside the vacuum motor 'can' that did this). There is a bypass valve in the vacuum lines between the headlight doors and the light switch that you can turn to shut off or 'vent' vacuum to the door motors so that they "fail-safe" to the open position. These doors are not run off of electric motors. See following post for a fuller description of the system, where the bypass valve is and how to service.

[mcm51]

If push comes to shove, swap your headlight with headlights on, try to unplug first if possible, otherwise you'll have to work fast or have some good gloves, that headlight will heat up fast. If you have to do it this way, you won't have to mess with the doors in any way....Did it this funky way on a '78 I used to have....

[Alan H. Tast]

A vacuum by-pass valve is used to control vacuum to the headlight doors. When the body of the bypass valve, which is in-line with vacuum hoses between the light switch and the two vacuum motors (one for each headlight door) is rotated to 'vent' the system, vacuum is no longer getting to the 'cans' and, as a result, they will "fail-open" and expose the headlights.

The 1980 Thunderbird Owner's Manual illustrates the bypass valve - note the valve and rotation of it to 'open' the doors:
Headlight Doors - Manual opening (from 1980 T-bird Owners Manual pgs 23 & 24)

Headlight Doors - Manual opening (from 1980 T-bird Owners Manual p 23)

Headlight Doors - Manual opening-closing (from 1980 T-bird Owners Manual p 24)

The system is virtually the same as the '77-'79 T-bird and Lincoln Mark V, as well as the early '80's Mark VI. In fact, Ford's 1980 Service Highlights for Electrical Systems points out that the headlight door system is virtually the same as the previous ('77-'79 version).

Headlight door-motor (from 1980 Ford Car Service Highlights - Electrical Systems)

Because of the similarity (and because I don't have copies of the '80-'82 shop manuals), I'll use the following illustrations from the 1979 Ford Car Shop Manual, Vol. 3-Electrical to help explain the system.

Headlight Cover General Description (from 1979 Ford Car Shop Manual - Vol. 3-Electrical)

The headlight door motors, which are behind the headlight assemblies inside the front fenders, are spring-loaded (the spring is inside the vacuum 'can'). Vacuum from the engine also goes into a vacuum reservoir on the inside of the driver's (left) side of the front fender and is connected to a check valve, which is placed in-line between the engine vacuum and the headlight switch. This illustration is from the 1979 Ford Car Shop Manual for examples of the vacuum motors and the reservoir inside the left fender.

Headlight door vacuum motors (from 1979 Ford Car Shop Manual Vol. 3-Electrical)

On the back of the headlight switch there is a plastic manifold, called a distributor valve, from which vacuum lines run to the bypass valve.

Headlight switch with vacuum manifold (from 1979 Ford Car Shop Manual Vol. 3-Electrical)

The 1979 T-bird/LTD II/Cougar XR-7 Electrical & Vacuum Service Manual has this schematic for the headlight door system. It's important to note that one set of hoses is marked in yellow and the other in green - the hoses and bypass valve are marked with the same colors:

Vacuum Schematic - 1979 T-bird headlight doors (from 1979 Cougar, LTD II, T-bird, XR-7 & Ranchero Electrical & Vacuum Troubleshooting Manual)

The 1977-79 Thunderbird Owners Manuals virtually repeat themselves in describing how to open and close the doors manually. Below is from the 1977 T-bird Owner's Manual.

Headlight Door Manual Operation (from 1977 T-bird Owner's Manual p 19)

Headlight Door Manual Operation (con't) (from 1977 T-bird Owner's Manual p 20)

Notice that the instructions are very similar to what was used in the 1980 Owner's Manual.

Here's the 1979 Shop Manual's instructions on how to replace the headlights.

Headlight Replacement (from 1979 Ford Car Shop Manual - Vol. 3-Electrical)

And here's the instructions on how to diagnose door operation, test vacuum, replace the vacuum motors and reservoir.

Headlight Door Checks & Vacuum Test (from 1979 Ford Car Shop Manual - Vol. 3-Electrical)

Headlight Vacuum Door Troubleshooting, Motor Removal & Replacement (from 1979 Ford Car Shop Manual - Vol. 3-Electrical)

[Dave 82 Heritage]

Thank you!!! I got them figured out now thanks to your help!

Dave

[Dave 82 Heritage]

Thanks, I installed Sylvania Silver Star head light bulbs, big difference!

Dave

[mcm51]

Just wanted to comment on those silver star bulbs, I too have put those in my Bird many years ago and have been very happy with them. I see farther ahead and right to left than the o.e.m. bulbs, yes big difference. I'll run those silver stars till the day I die !!