71 headlights
Thread Starter
|
Junior User
Joined: Feb 2009
Posts: 52
Likes: 0
From: Rolla Missouri
71 headlights
Ive got a 71 3/4ton and when im driving at night with my headlights keep turning off. I turn the swtich off then back on and they come on. I think the thermal breakers are weak on it. Does anyone know where they are. I heard on the headlight harness and i have heard they are apart of the switch. Can anyone help me greatly appreciate it.
Senior User
Joined: Jul 2003
Posts: 290
Likes: 0
From: Las Vegas
I will guess that you have halogen or other higher powered/brighter than original headlights. Is this correct? The wiring and headlight switch in these trucks were just barely stout enough to handle the amperage draw of the original style headlights when the truck was new and after 35+ years the resistance has increased and if you compound that by upping the amp draw even a little bit, the switch and/or wiring will overheat causing the switch to do what you describe and or burn up the wires and/or switch. The absolute best upgrade you can do for your truck is to install a 2 relay system to power your headlights. With the relays you will only be using the existing headlight wiring to control the relays which is only a tiny amperage draw. Do a search and you will find several threads with links to instructions/diagrams/schematics for doing this upgrade. It is really very simple and you should do it even if you haven't upgraded your headlights. Check this link:
Whiter Whites, Brighter Brights .: Articles
You may wish to simplify by eliminating the forced low beam option, but this should give you a good overview.
Hope This Helps,
Gene
Whiter Whites, Brighter Brights .: Articles
You may wish to simplify by eliminating the forced low beam option, but this should give you a good overview.
Hope This Helps,
Gene
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
Not what he means...
If you replaced the Headlamps themselves with Halogen headlamps, or if someone did in the past, the extra current draw could be enough to trigger the thermal breaker in the headlamp switch.
The original stock headlamps were incandecent, not halogen.
If the headlamps are halogen, it will say so on the lamp itself somewhere on the lens face.
The thermal breaker in the headlamp switch can also get weak over time. Comon problem.
Or the thermal breaker is doing it's job, and you got a short in the wiring or defective dimmer switch somewhere, etc....
I'd go down the list and check the following...
1: Halogen Headlamps instead of incandecents... Replace the halogens with incandecent lamps, or upgrade wiring to handle Halogens. As mentioned by 68 horses in the tech article above... https://www.ford-trucks.com/article/...r_Brights.html
2: Weak Thermal breaker in headlamp switch. Replace switch.
3: Defective dimmer switch, or wiring... repair as necessary.
If you replaced the Headlamps themselves with Halogen headlamps, or if someone did in the past, the extra current draw could be enough to trigger the thermal breaker in the headlamp switch.
The original stock headlamps were incandecent, not halogen.
If the headlamps are halogen, it will say so on the lamp itself somewhere on the lens face.
The thermal breaker in the headlamp switch can also get weak over time. Comon problem.
Or the thermal breaker is doing it's job, and you got a short in the wiring or defective dimmer switch somewhere, etc....
I'd go down the list and check the following...
1: Halogen Headlamps instead of incandecents... Replace the halogens with incandecent lamps, or upgrade wiring to handle Halogens. As mentioned by 68 horses in the tech article above... https://www.ford-trucks.com/article/...r_Brights.html
2: Weak Thermal breaker in headlamp switch. Replace switch.
3: Defective dimmer switch, or wiring... repair as necessary.
Lead Driver
Joined: Sep 2003
Posts: 7,012
Likes: 204
From: SoCal
Halogen lights can be made with the same power as regular sealed beams, but they are typically made with the maximum power allowed by DOT (55/65 watts), which is higher than the old sealed beam lights (35/45 watts), so yes, they will be a bigger strain on the stock wiring and switches. It seems ALL Fords came from the factory with inadequate headlight wiring, and should be retrofitted with relays.
Thread Starter
|
Junior User
Joined: Feb 2009
Posts: 52
Likes: 0
From: Rolla Missouri
Thanks guys for everything. I spoke with a Ford truck guy here in Tacoma and he said he'd bet that its the switch is bad. So im gonna try that and if it dont work ill be back lol
Senior User
Joined: Jun 2009
Posts: 213
Likes: 0
From: anderson sc
used headlight harness from LMC #47-3660 and installed new head lights from summit raceing. Also upgraded alt. What a differance!!!
Trending Topics
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
Actually, they're both incandescent; ie, they both incandesce, or glow by heating a filament. The difference is the halogen light uses a small bulb around the filament to surround it with a halogen gas, which helps to re-deposit back onto the filament the metal that normally boils off the filament from the heat and deposits onto the inside of the bulb. This allows the filament to be run hotter with the same power or driven with more power and give off whiter light, and last longer than non-halogen filaments.
Halogen lights can be made with the same power as regular sealed beams, but they are typically made with the maximum power allowed by DOT (55/65 watts), which is higher than the old sealed beam lights (35/45 watts), so yes, they will be a bigger strain on the stock wiring and switches. It seems ALL Fords came from the factory with inadequate headlight wiring, and should be retrofitted with relays.
You can buy hi output Halogen replacements, but not sure how legal they are either.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Kyle, The switch could be bad, but the issue is long known about, has bothered many trucks on a 25 year or so build period.
As mentioned prior, pull your dimmer switch up off the floor and clean it, next to the light switch, try slipping the wires off and wiggling them back on. This can clean minor corrosion,
Adding the relays as per the article is a must do. I don't remember where I got my new sockets but everything should be available at your local favorite parts house. It is a very good upgrade for the truck
guluk
John
Thread
Thread Starter
Forum
Replies
Last Post
jsmith71
1987 - 1996 F150 & Larger F-Series Trucks
11
Feb 13, 2005 09:12 PM
