Upfitter switch problem - Diesel Forum

Lancelot · 12-01-2009, 05:55 AM

I installed a power inverter. Initially I thought it would be a good idea to wire it through one of my upfitter switches since I haven't found a use for them yet. Well I did this and there wasn't any power to the wire when I tried to fire it up. I found what I believe to be the correct wire, hooked it up, grounded it to a bracket that's bolted to the body under the dash, and nothing. The switch would light up when I turned it on, but no power to the inverter. ????????????? I don't get it.

FX4Driver · 12-01-2009, 10:21 AM

The switch will light up regardless of anything being connected - at least that's how it works in my truck.

jays2003 · 12-01-2009, 03:35 PM

Lancelot,

Where did you mount the inverter?

bigdawgkp · 12-01-2009, 05:13 PM

The conductors for the upfitter switches are not under the dash as in previous models, the wires are outside on the firewall. I too was trying to tie a CB radio into one of the upfitter switches and the wad of wires to the left of the steering wheel are not the wires to the upfitter switches. According to the manual the wires are outside the cab on the firewall. I was not able to confirm the conductors at the time I was working on the CB due to a medical response with the volunteer fire dept.

jackconst · 12-01-2009, 07:20 PM

The upfitter wires are under the dash to the left of the steering column. There are also four wires that are pass through wires that come out on the firewall. It sounds like you may of hooked up to one of the pass through wires instead of the upfitter wires. They are labeled but I do not remember what they say. It should say in the owners manual.

Lancelot · 12-03-2009, 05:43 AM

I mounted the inverter between the driver's seat and the console. attached to the console. I have received info back from Ford that gives the location of the fuses for each of the upfitter switches. I indicated earlier that the switch light came on only to imply that the fuse must be ok if this is the case.

Lancelot · 12-03-2009, 05:58 AM

The info sent by Ford is attached

senix · 12-03-2009, 06:14 AM

Quote:

Originally Posted by Lancelot

I mounted the inverter between the driver's seat and the console. attached to the console. I have received info back from Ford that gives the location of the fuses for each of the upfitter switches. I indicated earlier that the switch light came on only to imply that the fuse must be ok if this is the case.

any pics as I am trying to find the best location for a inverter as well. Don't think the upfitters would be able to handle the amps from a intverter though

Lancelot · 12-04-2009, 05:24 AM

Actually i don't think that a 400w inverter will pull a substantial amount of amps. There are two 30 amp circuits (aux 1&2). The manufacturer recommended that a 20amp fuse be installed inline if the unit were hard wired into a vehicle.

By the way, Ford has responded to me that the upfitter switch light is powered separately and there may be a blown fuse even if the switch lights up.

senix · 12-04-2009, 05:26 AM

Quote:

Originally Posted by Lancelot

Actually i don't think that a 400w inverter will pull a substantial amount of amps. There are two 30 amp circuits (aux 1&2). The manufacturer recommended that a 20amp fuse be installed inline if the unit were hard wired into a vehicle.

By the way, Ford has responded to me that the upfitter switch light is powered separately and there may be a blown fuse even if the switch lights up.

thanks for the info!

tntvetsch2 · 08-14-2010, 12:55 PM

I have a copy of Bulletin Q-117-R1 which shows the 4 blunt cut wires that are suppose to be on the wiring harness under the driver's side. They aren't there. There are about 15 blunt cut wires. I have found what I believe are the 4 pass thru wires that go from the cab to engine compartment, but am unable to find any wires to hook into that are controlled by my upfitters switches. Any help finding the wires would be greatly appreciated.

dieselmac · 08-14-2010, 01:56 PM

Lancelot -- A 400watt inverter can pull more than a 30amp circuit can provide. 400watts / 12 volts = 33.3amps (excluding inverter inefficiency of about 90%). This doesn't include in-rush current/start up load which can often pull up to 2x the amps. Granted, you shouldn't run an inverter that close to its limit; but if you do, you'll blow a fuse. I'd stick to the manufacturer's recommendation on a 20amp fused circuit.

If you're going to run anything more than 300watts through an inverter, it needs to be wired to the battery through a relay. Not the upfitters. You'll also need some pretty hefty wire. #4 wire at 12 volts and 30 amps is good for about 35 feet of wire length. After that you'll lose more than 5% voltage. I'd personally run a #2. That's good for about 55feet and gives you some factor of safety for all the extra heat the wire picks up from the engine compartment and would let you upgrade to a little larger inverter down the road without pulling new wire.

**KC8RXQ** · 08-21-2010, 01:20 PM

Quote:

Originally Posted by tntvetsch2

I have a copy of Bulletin Q-117-R1 which shows the 4 blunt cut wires that are suppose to be on the wiring harness under the driver's side. They aren't there. There are about 15 blunt cut wires. I have found what I believe are the 4 pass thru wires that go from the cab to engine compartment, but am unable to find any wires to hook into that are controlled by my upfitters switches. Any help finding the wires would be greatly appreciated.

tntvetsch2,

I went through the same issue with my 2010 F350. The local service manager faxed me a copy of what the factory sent to them and it's pretty much what was already posted. The wires are somewhat hard to find and it's easy to mistake those for the pass-through wiring that's right out in the open. Keep looking and I'm sure you will find the right ones.

Ed