Notices
1973 - 1979 F-100 & Larger F-Series Trucks Discuss the Dentsides Ford Truck
Sponsored by:
Sponsored by: Moser

Ground activated fan relay

Thread Tools
 
Search this Thread
 
Old Mar 23, 2015 | 01:54 AM
  #1  
F-250 restorer's Avatar
F-250 restorer
Thread Starter
|
Lead Driver
15 Year Member
Photogenic
Liked
Loved
Joined: Mar 2008
Posts: 7,182
Likes: 380
From: Near Los Angeles
Ground activated fan relay

Hello all: I am changing from the radiator probe type thermo control to a three prong vw ground activated thermo switch. I am currently using this wiring:



Is it possible to run the ground from both relays through the ground terminal on the switch, and low speed, terminal 2, would go to ground, completing the circuit? Is that kosher?
 
Reply
Old Mar 23, 2015 | 08:25 AM
  #2  
HIO Silver's Avatar
HIO Silver
Fleet Owner
Joined: Dec 2009
Posts: 20,678
Likes: 82
From: NorCal
But what are you trying to accomplish by doing that?
 
Reply
Old Mar 23, 2015 | 12:25 PM
  #3  
F-250 restorer's Avatar
F-250 restorer
Thread Starter
|
Lead Driver
15 Year Member
Photogenic
Liked
Loved
Joined: Mar 2008
Posts: 7,182
Likes: 380
From: Near Los Angeles
My radiator probe caused the radiator to leak. So I am trying to find a trigger that will be dependable. Hence the VW Audi thermal switch in the radiator line.

Is there/would there be a problem wiring it that way? Doing it that way mean not having to rewire the entire system. The VW switch is ground activated. Or would it be better to run the fan grounds through the switch?

Thanks for the reply. After doing a bit more research on various online articles of 'how to', I have found that triggering the ground is a fairly common way to wire it, and actually the recommended method. Cheers.
 
Reply
Old Mar 23, 2015 | 12:51 PM
  #4  
tabascom16's Avatar
tabascom16
More Turbo
15 Year Member
Photogenic
Photoriffic
Shutterbug
Joined: Apr 2007
Posts: 656
Likes: 5
From: Salisbury, PA
Run the relay grounds through the switch , not the fans. The fans likely pull too much current and will fry the switch. That is why there is relays on them in the first place. I want to see pictures of this setup when you are done. I want to go electric with fans automatically turning off and on.
 
Reply
Old Mar 23, 2015 | 01:33 PM
  #5  
F-250 restorer's Avatar
F-250 restorer
Thread Starter
|
Lead Driver
15 Year Member
Photogenic
Liked
Loved
Joined: Mar 2008
Posts: 7,182
Likes: 380
From: Near Los Angeles
Originally Posted by tabascom16
Run the relay grounds through the switch , not the fans. The fans likely pull too much current and will fry the switch. That is why there is relays on them in the first place. I want to see pictures of this setup when you are done. I want to go electric with fans automatically turning off and on.
I am still using the diagram I posted. The changes will be the keyed 12v will go straight to the relays since I'm deleting the insert type adjustable control. The probe put a hole in radiator! The other change is I'll be using high/low VW/Audi thermo switch in the top radiator hose, and the relays will ground through that switch. You can also drill/tap your thermostat housing and install the switch there. It is M22 x 1.5 threads.

I have dual fans and wire them independently so if one fails I still have cooling. I also have a back up/spare switch, one in the radiator hose, one in the thermo housing. I use the fan out of a Ford Contour/Mystique, with the 16 valve engine. It moves 3500 cfm. I took the relays from a Taurus.

If you search the forum under Contour fan, you'll find the thread. I would convert to the 3g alternator from a Taurus first.
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
oldmongo
1987 - 1996 F150 & Larger F-Series Trucks
8
Jun 16, 2012 11:19 PM
IamMeYouAreYou
Cooling, Heating, Ventilation & A/C
1
May 4, 2012 09:36 PM
JRS75f100
1973 - 1979 F-100 & Larger F-Series Trucks
3
Sep 11, 2011 03:37 PM
Woodsman_30350
1948 - 1956 F1, F100 & Larger F-Series Trucks
4
Feb 25, 2009 07:15 PM
53Merc
Cooling, Heating, Ventilation & A/C
3
Dec 6, 2003 03:01 PM




All times are GMT -5. The time now is 12:12 PM.

story-0
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-1
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 09:39:23


VIEW MORE
story-2
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-05-30 18:33:59


VIEW MORE
story-3
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-4
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE
story-5
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE
story-6
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

And it might be even better than that.

By Brett Foote | 2026-05-18 19:26:42


VIEW MORE
story-7
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

Slideshow: Does lowering an F-150 Lobo RUIN the ride quality?

By Michael S. Palmer | 2026-05-18 19:20:37


VIEW MORE
story-8
Ford's 2001 Explorer Sportsman Concept Looks For a New Home

Slideshow: Ford's bizarre fishing-themed Explorer concept has resurfaced after spending decades largely forgotten.

By Verdad Gallardo | 2026-05-12 18:07:46


VIEW MORE
story-9
10 Best Ford Truck Engines We Miss the Most!

Slideshow: The 10 best Ford truck engines we miss the most.

By Joe Kucinski | 2026-05-12 13:09:47


VIEW MORE