Thane-
Ford provides the inputs to the tail/park and clearance wiring, but Tiffin does what it wants to get it to the lights. I can tell you what Ford did. For the Tiffin end you'll want to call them. (Ordinarily I look this stuff up, but didn't want to have to register on Tiffin's Web site to do so- if they'd let me, that is.)
For a Ford chassis, a great place to start is to look at the
Body Builder's Layout Book for the correct year. In your case, I assumed the chassis is a 2001, but it could be a 2000. Here's
a link to the 2001 F53 chassis wiring information. Sheets 4 and 5 in that PDF show the fuse and relays. Fuse #6 in the Power Distribution Box (PDB) is the "marker lamp feed." On a
2006 F53 chassis (for which I have wiring diagrams), this fuse supplies 12V to the following, when the headlight switch is in the "Park" position:
1) Instrument panel illumination (via interior fuse #41)
2) Trailer Electronic Brake Control
3) For use by Body Builder (front of chassis)
4) For use by Body Builder (rear of chassis)
5) Front park lights
Ford doesn't change its wiring much from year to year, so it's possible that the same applies to your 2001.
One conclusion you draw from the list above is that if fuse #6 has failed, the front park lamps should not work, either. While you're at it, check the status of the front clearance/marker lamps.
As "twinboat" said, the headlight switch could have failed, as it will (generally) have the same symptoms as if fuse #6 is blown.
The PDB is found under the hood, in the approximate center of the firewall, near the top. If the auxiliary relay box is below the PDB, the PDB door hinge is on the right, and opposite if the auxiliary relay box is above the PDB. There's a cover latch on the side of the end opposite the hinge. Here's
a link to a post I made that includes a photo of the PDB (sometimes called the "BJB," for "battery Junction Box").
Let us know what you find.
Linear Mode
