2000 Ranger - unknown connector under dash

[SteveK]

Howdy all -

While I was doing a light restoration / refresh on my 2000 Ranger, I added heated seats. Im doing final assembly today and was looking for a circuit to tap into.

While peering under the dash, I found this unused connector.

Question #1 - Anyone have any idea what it is?

I have not poked it with a VOM to see what it does (yet)

My 03 F250 has a few "upfitter" circuits under the dash and I was hoping to find something similar on the Ranger.

Basically, I am looking for "key on" 12 volts. I have considered taping into the "key on" circuit for the radio and use it to switch on a relay for power to the heated seats.

Question #2 - Has anyone done a power seat retrofit and if yes, what circuit did you tap into?

SK

 

[Dirtman]

Power heated seats are going to draw too much current to safely tap into an existing circuit unless you are only using it for the signal power to the relay in which case anything key on 12v is fine. Radio, wipers etc.

 

[SteveK]

Power heated seats are going to draw too much current to safely tap into an existing circuit unless you are only using it for the signal power to the relay in which case anything key on 12v is fine. Radio, wipers etc.

Thanks for the response... the relay route is exactly what I am thinking.. In my "perfect little world" I am hoping there is an unused connector I can plug into rather than hacking into the existing harness.

The connector in the pic in the original post caught my attention. It had a "blank" cap over the end of it. I have not probed it yet.....

SK

 

[Dirtman]

I cant say for sure but 3 things come to mind, radio connection for the factory premium sound system with the amp and what not, brake controller harness (dunno if they were ever installed direct at the factory), or something for a factory alarm.

 

[Ramcharger90]

Is your truck automatic? And is it where the clutch pedal would be? That looks very similar to the plug in my 90 for the clutch interlock switch.

I know Ram used basically the same harness in the 1500s in all the sub models. Thats why you can buy an express and give it some Laramie or Big Horn trimmings.

So maybe Ford did the same for a while...

 

[SteveK]

....it is indeed roughly where a clutch pedal would go. 6 pins.

 

[SteveK]

...truck is an automatic.

 

[Ramcharger90]

More than likely that's what its for.
I dont know if you should use that but one of the pins probably has 12vs going to it with key on.

 

[adsm08]

That's the plug for the clutch switch.

I'd check that blank cap closely for jumper pins. It probably has shorting bars in it to complete the circuits the clutch switch would close. If so the truck won't crank with it unplugged.

Rangers never got upfitter circuits.

 

[SteveK]

As always, thanks for the smokin fast responses - especially the insight into the shorting bar.

.. alternate strategy. By probing the fuse box, I discovered a few unused fuse spots that are 12V with key on. I am going to run to Autozone and pick up a few "add a circuit" fuse tap and see if I can make that work..

Any thoughts on this?

I think it should work...

SK

 

[Dirtman]

That will work fine. Signal power to a relay is extremely low current.

 

[SteveK]

.. actually, my idea is to just use the "add a circuit" fuse tap and call it day. That is, without relay. In my mind, this would be a lot safer than running a new "hot" all the way from the battery, through the firewall, etc. There are not a lot of "extra holes" in the cab that I could find - unlike the 60's era muscle cars.


Thoughts?

SK

 

[Dirtman]

You'd need to know the draw of the seats and the wire guage of the circuit you tap. You could tap into something with 18 or 20 guage wire when your seat heaters require 12 or 10 etc. Or the circuit could run through the PCM or another module. For low power items I wouldn't even hesitate but heated seats probably draw a large amount of power. A relay is much safer than tapping blindly into a circuit.

 

[SteveK]

Gotcha and understand. The power seat harness has two inline fuses. One for left side seat and the other for the right. As received, each had a 10 amp fuse in them, so total of 20 max. The power feed wires to the seat heaters can not be any larger than 18 ga. - I am actually very surprised at how small they are.... So... I am actually thinking they can not be more than 5 amps per seat. (reversed into amp load based on wire size using calculator at wirebarn.com - 13.8 volts, 5 amps, 6 foot harness length, 2% drop).

I probed the fuse box in great detail - fuse slot number 12 is listed as "unused" in shop manual and owners guide but is 12V at "key on". Indeed, looking at the back side of it, there are no wires coming out of position 12. My theory is this 12V source is internally off the main power feed to the fuse box, but I did not take it apart to look (yet). I very well may pop the top cover at it to have a look and make sure it isnt bridged to something else.

My reservation in running a new power feed is I just ran a temperature sensor feed into the cab (I did the explorer over head console retrofit). There are *very* limited spots to sneak a wire through the firewall - my worry is that if I jam a power feed directly from the battery through the one hole I found and used for the temperature sensor, over time, it will chafe and short against the firewall (zap!).

so, provided I do not torch the fuse box, taping into this unused "key on" circuit just seems a better option from a long term point of view.

I think I am going to have a try of it and drop the inline fuses in seat harness down to 5 amp and see what happens.

SK

 

[SteveK]

Update:

Pulled face off fuse box to see what I was working with.

Fuse positions 12 (unused), 16 (windshield wiper motor), 30 A, and 20 (radio, RAP, GEM) 7.5A all have same main power feed and are tied together. I checked continuity with fuses pulled and battery disconnected. Given the windshield wiper motor is on this feed, you are correct, probably not a good idea to toss another 10-15 amps onto it.

Windshield wipers running and heated seats on is a very likely scenario.

In the picture, fuse position 12 is the one with the VOM probe on it, 16 is below it, and 20 below it. I believe the round metal projections are actually part of a localized buss bar within the fuse panel.

so, current plan is use position 12 as "key on' signal to a relay. There are several other spots in the fuse box that are not used and 12V power "key off" - so I am I am going to probe these and see if there is one that is suitable to use as a power feed - still trying to avoid pulling a new 12V feed from the battery through the cab firewall.

SK