Vaccume switch on fire wall?
Thread Starter
|
Senior User
Joined: Nov 2014
Posts: 139
Likes: 1
Vaccume switch on fire wall?
I looked under the hood of a 1975 f100 and seen a vaccume switch on the firewall , behind where the motor would set. Almost in the center, up by the top.
It has a port and one side is grounded( soldered to the switch) other wire I don't know where it went.
And idea what it's for?
And what's it called?
Thanks
It has a port and one side is grounded( soldered to the switch) other wire I don't know where it went.
And idea what it's for?
And what's it called?
Thanks
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
I'll bet your truck has a "low fuel economy" light in the instrument cluster. That's the switch for it. This was a '75 model year only option.
Is this the switch? And here's the light on the dash.
Is this the switch? And here's the light on the dash.
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
No HIO, I sure don't. I don't have any info on the switch. The manuals are kinda sketchy on this part.
Fleet Owner
Joined: Dec 2009
Posts: 20,678
Likes: 83
From: NorCal
10-4. The Edelbrock E-Street EFI has a vacuum readout which lead to my curiousity. I just did an MPG loop on my '70 and noticed its sensitivity when just going up a slight incline. I babied it as best I could but the aero drag on Bumps is like a barn... not just its door. 17 MPG out of an FE ain't too bad for the first time out. It needs a couple degrees of timing put back in cuz she popped and sneezed at couple of times at WOT.
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
Wow, 17MPG, not bad at all. Even if it wasn't dragging the whole barn behind it, an FE and good MPG usually don't go together.
Trending Topics
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
Yeah, I always thought that light was kinda ironic on our trucks. They should've just hard wired it so it would stay on all the time.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / Worst Features Of The 2025+ Ford Expedition
Brett Foote
10 Ways Ford is LOSING to the Competition
Joe Kucinski
Top 6 Best Deals Available on New Fords & Lincolns Right Now
Brett Foote
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Verdad Gallardo
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
Thread
Thread Starter
Forum
Replies
Last Post
48' fordster
1948 - 1956 F1, F100 & Larger F-Series Trucks
13
Sep 26, 2007 10:04 PM
jklimko
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
2
Oct 20, 2003 10:07 PM