Power Distribution Relay Box?

[ParadiseComputer]

It is OEM you can tell. I do have all the original books and this is not in it. Great, I have a unicorn.
I went ahead and pulled that one large relay and did a continuity test at 30 and 87a, it was open. So I dropped it on the ground and tested it again and, surprise, it was closed. I now have 12 v. at fuse 4 in the mini fuse block (Engine Fuse Module) on the fender well. And with that I have running board lights. So, although the problem is solved, I would like to know if any other owners have that relay block.

Welcome to my world! I too have that same fuse box on my 97' EB 4x4 4.6L. I was having the same problems with my running board lights. I tracked it down to the relay under driver side dash. 2nd relay from top on left side. It also controls the battery saver circuit. I have looked everywhere for explanation of these relays, but found nothing so far. I have a Chilton book for 97' - 03', but no mention of this relay block anywhere, not even in pictures. It may just be spare relay holder, but then again, why would it be wired if it was just a spare.

 

[Bedrck47]

Welcome to my world! I too have that same fuse box on my 97' EB 4x4 4.6L. I was having the same problems with my running board lights. I tracked it down to the relay under driver side dash. 2nd relay from top on left side. It also controls the battery saver circuit. I have looked everywhere for explanation of these relays, but found nothing so far. I have a Chilton book for 97' - 03', but no mention of this relay block anywhere, not even in pictures. It may just be spare relay holder, but then again, why would it be wired if it was just a spare.

FYI If you look at the owners manual it doesn't show that style of fuse box and even the Factory Service Manuals which are far better than the generic after market manuals do not show that style of fuse box

 

[jseales]

The VIN shows my expy has a "heavy duty towing package", I wonder if it is part of that. At some point I will track some of the wires coming from the relays. Not an easy task as it is taped into the larger Power Distribution Block, like I said...factory installed.
I bought the ford service and repair dvd, it has schematics for everything except that relay block. The truck was built in Michigan and started service in Oregon, so nothing weird there.
So, since it is a unicorn, does that mean I can sell it for more money? Just kidding, I bought it with 190K on it and it still drives like a beast...hope to get another 200K out of it.

 

[ParadiseComputer]

FYI If you look at the owners manual it doesn't show that style of fuse box and even the Factory Service Manuals which are far better than the generic after market manuals do not show that style of fuse box

I know, the best answer I got was last week when I did a wifi network repair for a guy at his vacation home. We got to talking, and found out he used to work for Ford. I asked him if he knew anything about this fuse box...he replied "You mean the one that doesn't exist on paper?". Yuup.
Apparently, these were put in as part of the standard repair procedure for one of the electrical system recalls. They were basically just generic panels that they used. He said even if there was a picture of it he wouldn't trust it since the actual order in which the relays were rewired would change so much from one repair location to the next. One dealership would perform rewire in one order, while dealership on other side of town might perform same repair in different order. Not that either one is incorrect, just different location for each specific relay. Hence the reason why there is no documentation on it.

 

[Bedrck47]

Thank you for that information.

 

[jseales]

I know, the best answer I got was last week when I did a wifi network repair for a guy at his vacation home. We got to talking, and found out he used to work for Ford. I asked him if he knew anything about this fuse box...he replied "You mean the one that doesn't exist on paper?". Yuup.
Apparently, these were put in as part of the standard repair procedure for one of the electrical system recalls. They were basically just generic panels that they used. He said even if there was a picture of it he wouldn't trust it since the actual order in which the relays were rewired would change so much from one repair location to the next. One dealership would perform rewire in one order, while dealership on other side of town might perform same repair in different order. Not that either one is incorrect, just different location for each specific relay. Hence the reason why there is no documentation on it.

WOW...just wow. Thanks for the info.

 

[ParadiseComputer]

I was checking out the F-150 forum *cough* 2 floors down *cough*, and came across this post:

https://www.f150online.com/forums/electrical-systems/448794-fog-light-relay.html

My mystery relay panel box is in same location as this one, but instead of the large relay in the middle, mine is all smaller in middle with large one near the top/left. I bet they probably are the same except for the order.....maybe.

Not my picture. Pic belongs to SSCULLY on F-150 forum *cough* 2 levels down *cough*

 

[jseales]

I found that when i started my google searches. If you look at my original picture, the large one runs both the trailer battery charger (when running) and the running board lights (when off). I have not started tracking down the wires with an ohmmeter, but I imagine all those relays are probably for the heavy duty trailer wiring.

 

[tinkering]

I found that when i started my google searches. If you look at my original picture, the large one runs both the trailer battery charger (when running) and the running board lights (when off). I have not started tracking down the wires with an ohmmeter, but I imagine all those relays are probably for the heavy duty trailer wiring.

I know this thread is 4 or 5 years old but I am having probs with running board lights too. I think I might have a similar relay box to 'the unicorn'. Mine is Oct 1997 (XLT). There are two rows of relays, see picture. How do I find which one is the culprit? I think I might just run a known good relay through the ranks.

 

[tinkering]

Well, that was easy. It was the first one I tried; the only large one, at the top right. I knocked it around a bit and I worked again but I replaced it with the known good one, just in case.