M1088 fuse block nightmare!

[thetruckguy]

Soooooo, not a fan of the spaghetti mess under the fuse block. It was nice when they labeled every wire so you could locate things easier. On my new FMTV tractor, there is one fuse socket (cb44, "trailer tail lights") that appears to have melted. The wire coming off the fused side is missing (the one that caused the melting). There is a socket missing out of the relay for (K31) "hazard warning", that appears to be the power supply slot. There is a random wire that was sticking out with what appears to be the correct plug to plug into the empty slot at "k31" but it looks like it had a second wire crimped (poorly) in with the one that is still there, and there is evidence of a little wire casting melt. There is also a path of destruction leading from the burned fuse, to where the empty socket is. The random wire leads to the power supply side of "cb74-hazard switch", which also jumpers over to power the fuse for "CB71-flasher". So, I took an educated guess, and connected another wire into the lonely plug, then put it in the lonely socket at k31, then took the new wire and connected the other end to an inline fuse (15 amp), then plugged it into the power supply side of the melted socket. Doing so, gained me brake lights, but still have no turn signals or hazard warning lights. Park lights and headlights are fine. I am guessing the flasher unit is shot. If anyone can find a wire schematic for the flasher system please let me know! Here are some pics for reference.

 

[thetruckguy]

At first I couldn't understand how these all connected, but according to the tm's, cb44 actually is "24v intervehicular right and left turn, tail, and brake lights" for wtec III trucks. Cb71 is actually "hazard warning switch, turn signal flasher, and work light switch". Cb74 is actually "turn signal flasher ECU". And K31 actually controls "12v intervehicular right composite taillight assembly". Confusing huh?

 

[thetruckguy]

Also, troubling me is the volt meter on the dash and all the marker lights are pulsing, steadily and not steady. They are not dim though. Maybe voltage regulator? I did upgrade to the 200 amp dual voltage alternator, with the regulator on it, but was there something else I should have upgraded with it?

 

[gimpyrobb]

I don't have any info to offer, but that looks like a very well laid out power center.

 

[coachgeo]

Does you truck have WTechIII tranny shifter? A search in here should help you find needed info to identify if yours is WTech II or III

 

[Suprman]

Make sure nothing is connected to the AC terminal on the regulator.

 

[thetruckguy]

It is a wtec III. Which is the AC terminal? I will snap a pic of the alternator later.

 

[NDT]

1998 trucks and after are WTEC III. I cannot stress the importance of putting the "fuse block", actually "PDP", back to the factory configuration. All correct p/n relays and breakers in the proper spots. If the sockets are burned up, you may have to carefully relocate those circuits to an unused location.

 

[Suprman]

I have the terminals and plastic tabs for the block. On the alternator regulator are 2 terminals. One marked 24v and one marked AC. 24v terminal is excite & regulation. For 12v regulation it divides. AC terminal is an AC output to drive a tach or accessory. Don't connect anything to it.

 

[thetruckguy]

Oops! That is probably my problem then! I will snap a pic in a little bit of how I hooked it up before I touch anything again.

 

[thetruckguy]

 

[thetruckguy]

 

[thetruckguy]

This wire is #110

 

[thetruckguy]

 

[thetruckguy]

On the voltage regulator, TL110 is plugged into the rear terminal with a white plastic insulator marked "F-". TL35 is plugged into the front terminal with the red insulator marked "E".

 

[Suprman]

The E terminal should be excite and regulation.

 

[thetruckguy]

Is there a different harness that comes with the 200 amp alt? When I installed it, I was able to find reference for the tl35 going on to terminal E on the regulator, but nothing definitive on TL110 or terminal F-. I assumed the wire had to go there, given its proximity. I can't imagine it just being left to dangle, but it looks like it did go somewhere on the 100 amp alternator.

 

[Suprman]

Not for the regulator. The 24v regulation excite lead needs to be on the front terminal of the regulator. Nothing should be on the back terminal and the extra wire can be taped off.

 

[thetruckguy]

OK, cool. I will try that tonight. I was trying to find the TM for installing the 200 amp upgrade kit for reference, but I can't dig it up now. I think I have the right wire on the E terminal, so I will just disconnect the F-.

 

[thetruckguy]

So, i disconnected the wire from the F- terminal and the voltmeter is still pulsing. The more lights i turn on, the worse it gets. The lights are pulsing too. I am not sure what wire 110 was for on the 100 amp alternator, but is it likely it damaged the regulator having it mounted to the wrong lug?