I will check those relays. I assume I can put 12v's to it and it should click? How else do you test relay. Also, I DO have A/C and it works. So.......

 

OK,sorry to high jack this thread,but it's the same thing(i know guys i'm bad about highjacking a thread),but i replaced BOTH of the relays in the doghouse to the side of the fuse box,i also replaced the #16 30 amp fuse and still have no power to the camper batt.,the way i'm checking is with a multi meter i get 12.85 volts without the switch on,but then when the truck is running,i still only get 12.85 volts......thoughts...???

 

12.85..... What is the output at your truck batteries?

 

The 12.85 is what you are getting out of your batteries.... What is coming out of your Altenator should be around 13.5v. This is what you should have on the 2 oclock high pin at the back of your truck. this should only be 'hot' when the truck is running and push around 13 v. If this pin is 'hot' when your truck is not running and you are plugged into your camper, there is a big chance you can run down your batteries on your truck when you use your camper 12v 'stuff'.... What do you have volts wise on the 2 o'clock pin with the truck running and not running.
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Quote:
<TABLE cellSpacing=0 cellPadding=6 width="100%" border=0 itxtvisited="1"><TBODY itxtvisited="1"><TR itxtvisited="1"><TD class=alt2 style="BORDER-RIGHT: 1px inset; BORDER-TOP: 1px inset; BORDER-LEFT: 1px inset; BORDER-BOTTOM: 1px inset" itxtvisited="1">schlepprock250OK,sorry to high jack this thread,but it's the same thing(i know guys i'm bad about highjacking a thread),but i replaced BOTH of the relays in the doghouse to the side of the fuse box,i also replaced the #16 30 amp fuse and still have no power to the camper batt.,the way i'm checking is with a multi meter i get 12.85 volts without the switch on,but then when the truck is running,i still only get 12.85 volts......thoughts...???</TD></TR></TBODY></TABLE>


For the '99 F-250... Scroll down to Pages 148...Fuse #24 10A "trailer tow battery charge relay coil...."

Scroll down to Page 151.... Fuse #16 30A "trailer tow battery charge"

Scroll down to Page 152.... Fuse #39.... --"Empty"-- (no fuse in it) "trailer tow battery charge relay"

https://www.fleet.ford.com/maintenan...ls/results.asp
Hope this has helped.

 

his is lower then mine..mine reads 13.4..i think that is the reason i went though 3 GP relay's in one winter... i now have a stancor 903 in there..its a 15V rather then a 12 V with everything else being the same...the 903 has been trouble free for 2 years now.. very good info brother les...im learning here as we go..

 

Correct,I have ALL maxi fuses,both relays I put in new today(39 and 40),and like I said 12.85 wether it's running or not.Brakes on camper works(new P2 Prodigy),all lights on camper works,I just don't think the batt. is charging.

 

This might get confusing if we're attempting to diagnose two different trucks.

It might be well if you could start another thread.

Pop

 

LOL...you're right Pop...I should not have taken over this thread...sorry to the original poster.

 

The relay that feeds the trailer battery charge power to the trailer needs to only be active when the truck is running. if its active when the truck is off, the trailer 12v system will draw from the truck batteries, not good. That is why you have to a relay in the circuit

 

Ok Pop, hopefully we can get back to my issue. This pic you sent seems to be different thing the one on #43, mine does not have 2 doghouses, only one and it goes left to right and has 2 relays in it. So where do we go from here?

 

So your truck didn't come with the factory trailer-towing package. Just because it has a hitch doesn't mean it did. You DO have the "FACTORY" rear 7-pin and 4-pin harness, don't you? Or has this hitch been added by an aftermarket company? You should be able to tell from how the wires from the rear plugs run to the truck's rear wiring. If they plug in, probably factory. If they are spliced and taped, probably not.

When the truck got a dealer add-on, it came with a "doghouse" with two cables coming from it. To install this doghouse, you disconnected a harness connector under the hood, and plugged the cable's connectors between the dis-mated ones.

You don't have that cable, and will need to either find one, or fabricate one. I don't recomment that you attempt the latter, as the proper materials will be hard to locate.

Now, you need to find the part number of that cable. Google is your friend, but maybe PartsguyEd can be of some assistance. If Ed can't find it, NumberDummy can.

This will give you the needed relays to isolate these two trailer functions from your truck's wiring. You really want this, as ALL trailer functions are isolated for the truck's protection from faulty trailer wiring. And it's out there, believe....

I'll ask NumberDummy for you.

To monitor his response, see this thread:
https://www.ford-trucks.com/forums/9...mberdummy.html

Pop

 

good info Pops..wish i could rep ya.....

 

Wow, a lot of info, I assume it's the factory 7 & 4 pin. though the plug was not mounted in the hitch. I moved it to the left hole of the frame mounted hitch. There is a plug from main harness to the 7/4 pin plug in, only two wires look spliced (maybe factory, never seen this style splice). It's a blue wire that I know runs trailer brakes (tested), then a black wire that is/was spliced to a orange wire on main harness, this should run battery charge, but I can't get any tester/reading from it. After that I'm not sure what you are saying about a cable.

 

Help, did everyone give up on me?