Ok, so in the 2016-2021 rebuild of my '88 bronco, i added a bunch of electrical accessories to the bronco. OBA, ARB, electric fan, a line lock, a led lightbar, and some gauges (oil pressure, trans temp, wideband O2) on the a-pillar. I tried to do most of the wiring all at the same time, in order to keep it clean and organized.
Part One: Switches & Wiring
Jump to Part Two: Relay Box
Jump to Part Three: Winch Control
Jump to Part Four: Electric Fan Control
Jump to Part Five: Gauges
Jump to Part Two: Relay Box
Jump to Part Three: Winch Control
Jump to Part Four: Electric Fan Control
Jump to Part Five: Gauges
Part One: Switches & Wiring
Im using Carling switches which i purchased from OTRATTW. Specifically, i am using Contura II/III series of switches. The series is relevant, as not all series are wired exactly the same. They are 'lower independant' which means the large square LED lights up when the device is turned on, and the small bar across the bottom lights up when the dash lights are on. In the case of the winch switch, either light will come on when running the switch in that direction.
Im using Carling switches which i purchased from OTRATTW. Specifically, i am using Contura II/III series of switches. The series is relevant, as not all series are wired exactly the same. They are 'lower independant' which means the large square LED lights up when the device is turned on, and the small bar across the bottom lights up when the dash lights are on. In the case of the winch switch, either light will come on when running the switch in that direction.
To wire up the switches i bought 18AWG, 12 conductor wire from ShowMeCables. The switches are all low-current since theyre just triggering relays, so this was an easy way to neatly package a bunch of wires in a small space.
For power, i bought a waterproof fused relay box off of Amazon: Universal Relay Box
For power, i bought a waterproof fused relay box off of Amazon: Universal Relay Box
So lets talk about the wiring at the switches.
This is why using 12 conductor was a lot simpler than building and sleeving my own harness. It's a lot of wires! So lets start at the switches, and we'll make our way to the relay box from there.
First up, is the switch wiring diagram.
|
As mentioned, i am primarily using the Carling Contura II/III, however i am using a Contura XII switch to control the winch from the dash. So this is the wiring diagram for the Contura II/III.
|
|
Looking at the diagram, this would be something simple like turning on my ARB, line lock or light bar. Pin 7 is the ground for the switch and lower light. Pin 8 is the ground for the upper LED, so when you turn the switch on, the upper light will illuminate. Pin 2 is +12 in to the switch, and Pin 3 sends power out to the relay when you flip the switch. Pin 3 is also power to the upper LED, which is why it turns on with the switch on. Pin 6 is for the lower LED, which is wired internally to the ground, aka Pin 7. So applying power from the dash illumination to Pin 6 means the lower bar turns on when you turn on your lights. In a nutshell, power passes thru the switch via pins 2 & 3, and the others are power and ground for the switch's lights to work.
|
This is the wiring diagram for the Contura XII winch control switch.
|
|
Seeing as both lights are independent of switch position we have to power them ourselves, which is what you see here. Pin 2 is +12v in to the switch. Pin 1 is power out, aka 'winch out'. Here we have it jumpered over to Pin 8, which is power for the upper light. Pin 3 is the other power out aka 'winch in', this one jumpered over to Pin 6 which is power to the lower light. Both lights are wired internally to Pin 7, which is ground. Having it wired as pictured ensures the lights only turn on when the paddle is pushed up or down.
So now that we know how the switches get wired, lets actually wire them. Enter my hand drawn diagram from when i actually wired them:
12 conductor wire means we get 6 pairs. So we're using pairs for each switch. For example: +12v Blu to the ARB switch, and then the Blu/Blk wire sends power out to the relay box under the hood. The variable is the winch power switch since its a SPDT switch, and as such has 2 +12v outputs, to control both winch in/out. I chose to use Brn/Blk for the second output since this way i know every striped wire in my harness is a switched power, and every solid wire is a constant +12. This of course meant i had a single brown wire in the cable so i used that one as a 'key hot', meaning as soon as i turn the key on, it sends power out to my relay box to trigger some circuits that i want to run 100% of the time when the key is on, such as my OBA compressor & electric fan. This wire is fed by Fuse #17 in the OEM fusebox, which would be power for my non-existent ABS system.
All 4 switches get their power direct from the new relay box under the hood.
All 4 switches get their power direct from the new relay box under the hood.
Part Two: Relay Box
So now that weve got the switches wired up, lets look at the other end, the relay box.
So now that weve got the switches wired up, lets look at the other end, the relay box.
I installed the relay/fuse box in some open space over near the heater box:
With the box flipped upside down, you can see there is a decent amount of wiring going on here! Ive labeled it help make some sense of whats going on
So here's what were looking at. In the bottom left is the control wiring, aka the wires coming from our switches. All the power in/out from the switches comes right here to the relay box. The two power out wires from the winch control switch pass by the relay box and go right to the winch contactor, which is the two sleeved wires you see heading away in the top center of the image.
The 'main power' is six individual +12v wires coming from a power stud near the relay box.
Power out is the individual switched +12 coming from the output of the relays, and heading to their respective device.
System ground is the ground wire for the relays. This is a single wire because its only the ground for the relays, not the device theyre powering.
Before we get into the wiring for the relay box, here's a closer look at how the relays themselves are wired:
The 'main power' is six individual +12v wires coming from a power stud near the relay box.
Power out is the individual switched +12 coming from the output of the relays, and heading to their respective device.
System ground is the ground wire for the relays. This is a single wire because its only the ground for the relays, not the device theyre powering.
Before we get into the wiring for the relay box, here's a closer look at how the relays themselves are wired:
|
All of my diagrams are laid out as if youre holding the relay in your hand, upside down so you can see the pins.
Pin 85 is the ground for the relay. Pin 30 is the main +12v into the relay. When the relay is turned on, power will pass from Pin 30 thru Pin 87, which will then power your device. So this is the high current side of the relay. Pins 86/85 are the lower current switching side. So apply power to Pin 86 and the relay will turn on. |
|
Ok, so lets look at the wiring diagram for the entire relay box now.
Ok, theres a couple things going on here.
On the left is 5 Red +12v sources. This is the main power for everything. Each relay gets its own power source, and each has its own fuse. Youll note that i am using my Brown wire, aka 'Key Hot' from Fuse #17, to turn on the OBA compressor, and the elec fan relay. The OBA compressor is mechanical and requires the engine to be running to build air, so theres no need to have to manually turn this on. Instead, when i turn on the ignition, Fuse #17 will supply power to this relay, which will then in turn supply power to compressor clutch via the pressure switch.
Fuse #17 also turns on the electric fan relay, which in turn powers my electric fan controller (more on this later).
There is one thing not easily noticed in this diagram. In the diagram, power comes from the fuse and goes directly to Pin 30 on each relay. However, it also goes directly to each of the switches on the dash, meaning the switches are powered from the same fused source as each relay is. It would have been easier to just supply +12v to the switches from the dash, but i chose to wire it this way for 2 reasons. #1, if the switch is powered by the same fuse as the device its powering, if i develop a short and blow a fuse, all the others will continue to work. The second reason is because if, for example, i blow the fuse on the ARB circuit, then when i flip the switch on the dash the LED in the switch wont illuminate. So this is a super quick and easy way to troubleshoot a blown fuse when out on the trail. If the switch lights up but the device doesnt work, then i can assume the relay or the device itself has failed.
On the left is 5 Red +12v sources. This is the main power for everything. Each relay gets its own power source, and each has its own fuse. Youll note that i am using my Brown wire, aka 'Key Hot' from Fuse #17, to turn on the OBA compressor, and the elec fan relay. The OBA compressor is mechanical and requires the engine to be running to build air, so theres no need to have to manually turn this on. Instead, when i turn on the ignition, Fuse #17 will supply power to this relay, which will then in turn supply power to compressor clutch via the pressure switch.
Fuse #17 also turns on the electric fan relay, which in turn powers my electric fan controller (more on this later).
There is one thing not easily noticed in this diagram. In the diagram, power comes from the fuse and goes directly to Pin 30 on each relay. However, it also goes directly to each of the switches on the dash, meaning the switches are powered from the same fused source as each relay is. It would have been easier to just supply +12v to the switches from the dash, but i chose to wire it this way for 2 reasons. #1, if the switch is powered by the same fuse as the device its powering, if i develop a short and blow a fuse, all the others will continue to work. The second reason is because if, for example, i blow the fuse on the ARB circuit, then when i flip the switch on the dash the LED in the switch wont illuminate. So this is a super quick and easy way to troubleshoot a blown fuse when out on the trail. If the switch lights up but the device doesnt work, then i can assume the relay or the device itself has failed.
From there, its a simple +12v wire out of each relay to whatever device its powering. There are two exceptions though: the winch contactor, and the electric fan controller which we'll go over now.
Part Three: Winch Control.
The winch control does not go thru a relay in a box, since it needs to apply power to a reversing contactor.
First up, we're not connecting the winch direct to battery power, we're using a big mechanical disconnect from Blue Sea:
The winch control does not go thru a relay in a box, since it needs to apply power to a reversing contactor.
First up, we're not connecting the winch direct to battery power, we're using a big mechanical disconnect from Blue Sea:
This bad boy is rated for 600a continuous duty, and 1000a intermittent! So it is more than capable of handling the amount of current a typical winch motor will pull. To the left of it in the pic is a 500a reversing contactor made by Runva. Contactors are nice as they are simple and reliable, and fit in a smaller space than the typical solenoid pack you would use to power a winch. Lots of different manufacturers make them, but i would recommend you stick to a known brand, such as Runva or Warn, to make sure your winch actually works when you need it!
In this pic you can see i have power coming direct from the battery to the disconnect, and then from there to the contactor. The 3 large cables coming off the contactor go directly to the winch motor
In this pic you can see i have power coming direct from the battery to the disconnect, and then from there to the contactor. The 3 large cables coming off the contactor go directly to the winch motor
The contactor has 3 small screws on the top. This is how you control the contactor, and in turn, the winch
So we have main power going directly to the contactor, and that in turn reverses polarity to the winch motor to reverse direction. So the winch motor gets 4 large current wires (in my case, i used 2/0 gauge welding cable). Weve got 2 power wires going to 1 & 2 plus the armature wire, labeled A. Then of course we need to supply a large ground cable to the stud on the winch motor itself. If the winch runs backwards, you can swap the wires going to 1 & 2.
The switching circuit is those 3 small screws on the side, and is all low power. Ground to the middle, and then the two +12v wires from the winch control switch go to the outside lugs. If you have a wireless winch controller, youd wire it to these pins as well. If you look closely, you can see i squeezed in a Badlands Wireless Winch Controller in front of the battery in the core support:
The switching circuit is those 3 small screws on the side, and is all low power. Ground to the middle, and then the two +12v wires from the winch control switch go to the outside lugs. If you have a wireless winch controller, youd wire it to these pins as well. If you look closely, you can see i squeezed in a Badlands Wireless Winch Controller in front of the battery in the core support:
Theyre quite easy to hardwire into your vehicle; cut the plug off the end and connect via the diagram above. Now remember, when hardwired it will always have power! So i connected its +12v source to the input power to the contactor from the Blue Sea disconnect, this way it is only powered on when the winch is powered on.
So lets look at the wiring diagram now.
Part Four: Electric Fan Wiring
I am using a dual fan setup from a 2004-07 Ford Freestar, since it fits the stock radiator so well.
Dorman p/n 620-144
I am using a dual fan setup from a 2004-07 Ford Freestar, since it fits the stock radiator so well.
Dorman p/n 620-144
For my fan controller, i went to DC Controls and bought his FK-75 controller. It is a PWM controller, rated for 75a continuous duty, and is fully adjustable.
Since its PWM, the electrical circuit wont see a large load when the fan turns on. However, fans can still pull a decent amount of current, so i am using a 75a relay i bought from Obtain Surplus:
Here is the relay mounted between the winch disconnect & contactor, right next to the main relay box and fan controller.
This relay is still wired just like any other relay, just rated for higher current. So the power for the fan controller passes thru this, and when i turn the key on it powers up the controller automatically, so theres no chance of me forgetting to do so and accidentally overheating the engine.
Fan controller mounted on the fender liner, all wired up:
Fan controller mounted on the fender liner, all wired up:
Fans wired. They are single speed and get wired in parallel so they both run at the same time. You can see the temp probe wiring poking out of the loom:
Temp probe up close. Its a delta temp probe that installs right in the radiator fins, and it is remarkably quick to respond to temperature change:
So theres an input for A/C. When the A/C is on, it automatically turns the fans on at 50%. So i tied the signal wire into the output for the pressure switch, this way it only spins up if the A/C is actually turned on & functional.
So, if you were paying attention, you noticed an LED next to the switch for the winch control. Well, its for the electric fan:
This is a feedback sensor for the fan. When the controller first turns the fan on, it will blink red. Then, it will start off green. As the fan ramps up in speed, it will progressively turn yellow and then eventually red once its 100%, so you always know how fast the fan is spinning.
Part Five: Gauges
So ive added 3 gauges to the a-pillar. Top down weve got a wideband O2, oil pressure, and transmission temp. The two lower are pretty typical for me (ive had them in every truck ive owned), but ive added the wideband for the purposes of tuning the 466 that the bronco received at the end of its 2016-21 rebuild.
So lets start with the oiol pressure & temp, since those were installed first.
The gauges are from New Vintage USA, and are their Aviation series gauge.
The gauges are from New Vintage USA, and are their Aviation series gauge.
I prefer these since they match the OEM cluster fairly closely, altho i had them make them in green instead of the standard red. i think they match pretty good, and dont look all flashy.
The sensor for the transmission temp gauge is installed in the top of my remote filter housing (pic missing).
The oil pressure sensor is installed in a Tee in the back of the block (OEM location for a big block) so i could retain the OEM gauge int the dash. Sounds silly to have both, but i mainly kept the OEM one there in case of sudden oil pressure loss, so ill see two gauges (or the red Engine light) yelling at me.
The oil pressure sensor is installed in a Tee in the back of the block (OEM location for a big block) so i could retain the OEM gauge int the dash. Sounds silly to have both, but i mainly kept the OEM one there in case of sudden oil pressure loss, so ill see two gauges (or the red Engine light) yelling at me.
So lets talk about the wiring.
I decided to make a standalone harness for the gauges, complete with a plug on the end, so that the gauges & their harness can be removed for service later on without having to cut any wires. Having a ton of Ford Wedgelock connectors and pins, i used one of their 6 pins, to tie into the harness.
So each gauge gets a common +12, ground, and illumination wire. That leaves the other 3 pins for each sensor signal wire. So actually a fairly simple harness to build; only 6 wires in the column harness! So lets look at this mess under the dash:
|
It looks like a total mess, but its not, i swear!
In the top of the pic you see a brown plug thats not plugged in. Thats our 6-pin plug coming down from the column, that plugs into the one directly below it. Just below we see our power harness. I am using the +12 from the ABS system to power the gauges. Its a key-hot power supply that's fused at 15a, and since i dont have ABS, its an otherwise unused circuit. The ground goes to one of the harness grounds in the dash, and the illumination is of course powered from the dash circuit. The blue & orange wires exit thru the firewall and go to their respective sensors (oil pressure/trans temp). The wideband controller is mounted to the side of the pedal assembly, and uses the same +12 & ground source as the other two gauges, which is what you see in that loop coming out of the bottom of the controller. The controller has another plug (not visible) that runs over the pedal assembly and out the firewall to the wideband O2 sensor. In my case i am running an aftermarket ECU made by Stinger Performance which uses a wideband in place of the OEM narrowband, and as such i have the wideband sensor installed in place of the OEM sensor, as opposed to near it. |
|
The wideband sensor:
The wideband controller, a LC-2 from Innovate Motorsports:
The 4 small wires are power, ground and two sensor outputs, the large plug is for the O2 sensor and the two small ones are for tuning the sensor/gauge using their own software. Its actually a very simple gauge to setup and calibrate.
The 4 small wires are power, ground and two sensor outputs, the large plug is for the O2 sensor and the two small ones are for tuning the sensor/gauge using their own software. Its actually a very simple gauge to setup and calibrate.
The 3 gauge pod im using is from Glowshift, and actually fits surprisingly well. I did trim one corner slightly, but that's it. I marked it out and drilled holes to match the OEM trim screw locations, so i could use the OEM screw to hold their pillar in place over top of the OEM piece, which makes servicing the pillar much easier, rather than trying to remove those little push pins.
