IA F/S: 73-87 power window relay harness

[gmachinz]

I have a relay harness designed for any 73-87 pickup with power windows....less voltage drop for faster operating windows. $99 and I'm in Iowa.

[JMac11]

Interested, little more details.....
picture?

[gmachinz]

Here's a pic of the harness-it includes (2) relays for each door and each door has its own integrated control harness which splices in-between your switch and window lift motor-all the connections are made on the door-no cluttering up of the underdash to add this. The relays are HD commercial grade and are rated at 250,000 cycles so most likely you'll never have to replace one and are rated at 40A each.

The other nice things are that these allow you to remove the door without messing with pulling the switch through the door grommet and the relay bank will mount nice and stealthy right underneath your armrest base bracket on the door shell....that way, the molded door panel acts as a cover once you re-install it.

The point of this is to extend the life of the window switch and provide less voltage drop by allowing the relay to carry the load instead of the switch-aiding in allowing the windows to operate more quickly.



All the connections are soldered, heatshrinked and the wiring is j1128 spec Delphi automotive crosslink wire which is rated up to 257F and meets/exceeds OEM specifications, so you know this isn't a cheap parts store wire harness. Relays are a Bosch style but again, these are commercial grade and last 4X what a parts store Chinese one will-and, they have built-in tamping diodes as well. Very nice, quality harness kit.

I have 2 kits for 4-doors as well if anybody is interested....those are $179 ea. Again-these mount behind each door panel and take about 10 min. each to install with basic hand tools and a quality crimp tool-soldering the crimp connections you have to perform is recommended but not required. Let me know if you have any other questions!

[gmachinz]

1 sold....have 2 left.

[tucsonjwt]

Do you have a pic of the harness actually installed on a door, showing which wires go where and how the relays connect to the switch and harness to motor?

[gmachinz]

Yes, in the instructions I include details on how each wire is connected. Depending on where you want to mount the 2-gang relay bank on each door, you have to decide where on the OEM wiring you want to cut to make the connections.

I also include schematics of both the factory diagram and my modified relay schematic so instead of merely telling you what to cut, you can study both schematics to understand why it works before cutting or splicing any wires-I prefer to give people an opportunity to realize how easy relays can be to utilize.

[NewMexCrew]

Do you have a kit for a 4 door available?

[gmachinz]

I've had several requests for a 4-door...so, I have 2 made up right now if you're interested. This is a relay harness for all 4 windows.

[NewMexCrew]

Will they fit a 1990 GMC Crew Cab v3500?

[gmachinz]

Yes-if you have factory power windows, this kit is designed to convert all 4 windows to a relay powered system. Each window requires 2 relays and mounts on the door shell behind the lower panels. All wiring is labelled and my kits are color coded to be GM specific both in wire size and color for easy identification.

[rs74]

Is this harness basically the same principal of the other relay system? Where it gives you more power to the motor for better performance so you don't have the slow creeping window.

[gmachinz]

Yes.....this kit provides relay power to each window and the Express Down equipped harness is an addition to it-there are a few mods to the harness to rake advantage of the 1-touch down feature.

[rs74]

Thanks. I will keep this in mind. Once it starts to get warmer I will be starting to put the wiring back in the cab and will be getting new window motors to start off on the right foot. I will be in touch when that time comes. Do you do any of the headlight relay conversions? I have seen you also make the electric fan harness too.

[gmachinz]

Yes, I keep a few relay harnesses on hand. As for the trucks, my harnesses are complete from the firewall bulkhead connector out to core support with options for washer pump (depending on year) as well as horn and sidemarker circuits.....core support grounds included as well. I build my heeadlight upgrades as a complete harness replacement instead of pigtail adapter since most of the time, the old wiring is suspect anyway. Granted it costs more the way I provide them but I don't compromise when it comes to wiring. I build my harnesses exactly as I would prefer to use them.....as much an OEM appearance as possible while updating the options as well. Let me know when you're ready to decide, I can offer a group purchase discount for ya.

[gmachinz]

Here's a pic of the harness kit with the express down modules integrated.....so this gives you express down for both sides.

[gmachinz]

There's a wide variety of Express modules to be found amongst the GM brands....these happen to be 4th gen F-body spec'd modules. I have a bin of about 65 modules so far-all tested and perfectly operational. I have several projects on the design board with these modules in mind.

[gmachinz]

Originally Posted by rs74

Thanks. I will keep this in mind. Once it starts to get warmer I will be starting to put the wiring back in the cab and will be getting new window motors to start off on the right foot. I will be in touch when that time comes. Do you do any of the headlight relay conversions? I have seen you also make the electric fan harness too.

Yes-my fan harnesses differ from anything else you will find on the market-I worked (unsuccessfully I might add...) with Mark K. @ Spal some years back about designing a HD fan controller exclusively for the Mark VIII fan and other high output Motorcraft fans. I bought the OEM Motorcraft fans in large bulk from Ford for use in my relay harnesses I was building at the time for my shop customers. Well, two things happened:the fans went on the dis-continued list from Ford and Spal wasn't interested in building such a demanding controller for use with that or any OEM fan. Even their latest fan controller has an internal over current limit of 35 amps. If you try to run a fan that draws any more juice than that, it is designed to kick off.

Given what I know about fan motor efficiency I am not satisfied with any pancake style motor that Spal and most aftermarket companies offer so I was back to the drawing board. A rep for Siemens VDO out of Canada who designed/manufactured the fan motor for Ford informed me they (Ford) wanted a design that could run at full speed 24 hours a day for 10 years if need be...since that deisgn would see service in both high end Lincolns and police package vehicles. So I know from the horses mouth Motorcraft makes the most stout fans hands down.

Now, after reviewing the circuit design that Lincoln used on those fans called a VSC (variable speed controller) that they varied the speed by using a variety of capacitors of varying voltages to change the speed of the fan-not quite PWM but a more mechanical version of it. I figured the same thing could be accomplished through the use of a series of resistors to limit the voltage based on how many resistors the current must pass through-so I built a test harness and it has worked just like I planned from day one-I've perfected it over the last year and now, it serves as a conversion fan harness whereby it can allow you to take any fan-single or dual speed and use it as a 3-speed fan. My aim was to create a harness that can easily handle the demand of the Mark VIII fan since if it can do that, it can handle any fan you run it with, right? And, my relay resistor harness allows for 3 speeds out of it. Nobody else makes a non-PWM kit that can do that.

I just finished testing/running it on a dual 18" fan assembly from a 2010 F250 with the largest dual fan setup I've ever seen-it moves a reported 6000 CFM and pulls about 42 amps @ full speed to do it. I ran both fans at 3 speed in parallel and managed a 16, 28 and 42 on low, medium and high speed.

[NewMexCrew]

PM sent

[gmachinz]

PM replied!

[NewMexCrew]

PM Sent...

[SCOTI]

Originally Posted by gmachinz

Yes-my fan harnesses differ from anything else you will find on the market-I worked (unsuccessfully I might add...) with Mark K. @ Spal some years back about designing a HD fan controller exclusively for the Mark VIII fan and other high output Motorcraft fans. I bought the OEM Motorcraft fans in large bulk from Ford for use in my relay harnesses I was building at the time for my shop customers. Well, two things happened:the fans went on the dis-continued list from Ford and Spal wasn't interested in building such a demanding controller for use with that or any OEM fan. Even their latest fan controller has an internal over current limit of 35 amps. If you try to run a fan that draws any more juice than that, it is designed to kick off.

Given what I know about fan motor efficiency I am not satisfied with any pancake style motor that Spal and most aftermarket companies offer so I was back to the drawing board. A rep for Siemens VDO out of Canada who designed/manufactured the fan motor for Ford informed me they (Ford) wanted a design that could run at full speed 24 hours a day for 10 years if need be...since that deisgn would see service in both high end Lincolns and police package vehicles. So I know from the horses mouth Motorcraft makes the most stout fans hands down.

Now, after reviewing the circuit design that Lincoln used on those fans called a VSC (variable speed controller) that they varied the speed by using a variety of capacitors of varying voltages to change the speed of the fan-not quite PWM but a more mechanical version of it. I figured the same thing could be accomplished through the use of a series of resistors to limit the voltage based on how many resistors the current must pass through-so I built a test harness and it has worked just like I planned from day one-I've perfected it over the last year and now, it serves as a conversion fan harness whereby it can allow you to take any fan-single or dual speed and use it as a 3-speed fan. My aim was to create a harness that can easily handle the demand of the Mark VIII fan since if it can do that, it can handle any fan you run it with, right? And, my relay resistor harness allows for 3 speeds out of it. Nobody else makes a non-PWM kit that can do that.

I just finished testing/running it on a dual 18" fan assembly from a 2010 F250 with the largest dual fan setup I've ever seen-it moves a reported 6000 CFM and pulls about 42 amps @ full speed to do it. I ran both fans at 3 speed in parallel and managed a 16, 28 and 42 on low, medium and high speed.

I did a kit from you years ago that used the MVIII fan/PWM controller. Is your current non-PWM set-up what you would recommend now? What were the core dimensions on the F250 twin fan set-up?

I installed a SBC serptentine set-up on my BBC in my dually. I upgraded the therm clutch fan to severe-duty & increased the fan diameter to as large as the opening in the shroud but I'm not sure how well it will cool yet as it hasn't hit the TX summer months. I'd like to have a 'plan-b'.

[gmachinz]

The Spal PWM units work for lower amperage, less CFM pulling fans. They were never designed to manage the high current demands longterm of a lot of the OEM fans, including the Mark VIII. The first PWM had a limit of 35A sustained with a peak of 50A internally so you would think it would be a quality enough unit to still run a NEW Mark VIII with an average high speed draw of 28-32 amps.

And while I never had any issues with it, Spal changed the design to include an "overlimit" current so you couldn't run a high inrush current fan-otherwise it'd shut the controller down. That's when I gave up on Spal and decided to build my own relay setup.

The dual 16" Motorcraft fans measure 19"x34"x6.5" its a super stout fan assembly! The only harnesses I have that I would even consider is either my resistor 3-speed harness or a single speed, 100A relay harness which I use a unique relay incorporating dual resistors and dual series diodes.

[BLT gmc]

I will be in the market for an express down relay harness for a 85 C20 2 door this spring. Do you have a harness available? Price? Shipping to 51555 Thank you, Bruce

[gmachinz]

Bruce, PM sent! Thanks for the interest!

[slimneverdies]

Have a four door that I would like the express down feature.....