"Do not install fuse---" 2003 3500 Duramax

[Geo39]

My Owner's manual specifically states "Do not install fuse" in the fuse socket provided for power to my trailer. The truck came with the full factory trailer wiring harness, with a plug at the hitch and additional wiring for a plug in the bed. This warning is apparently specific to the diesel only - but no further explanation is given. I've tried the search function herein, but without results. The service manager at my dealership simply instructed me to go ahead and install a 40 amp fuse, however the RV dealer that will be setting up my hitch says that he adheres to the GM warning and hooks up the trailer power elsewhere. Can anyone explain this dilemma?

[jbplock]

Geo39,

This is news to me but I'm also not towing yet. I bought the 40 amp fuse but havn't used it. You might also try posting this question in the 2500HD/3500 HD Trucks & Drivetrain Forum (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=forum&f=7&submit=Go). smile.gif

[Hoppy1942]

News to me also. I'm really interested in the anwser since I'm getting ready to hook up for towing within the next couple of weeks.

[Geo39]

I took another look at the Owner's manual and - although the presentation sucks - it appears that what GM is saying is that "----if you have a single battery setup - or the dual battery setup common to the 3500 Duramax - plugging a 40 amp fuse in the socket is OK. On the other hand, if you have a dual battery setup - which is identified by a stated option "code" - don't plug a fuse in the socket! Just for sh--s and giggles, the exact verbage copied from page 5-109 of the 2003 Owner's manual, under "STUD #1" is "Auxiliary Power (Single Battery and Diesels Only)/Dual Battery (TP2) Do not install fuse." I suffer through technical specifications daily as part of my job and this verbage is about as clear as mud! If a period had followed the first part, rather than a slash, the second part might have read "With dual battery option TP2, do not install fuse." Is this the correct interpretation - or are we to avoid installing a fuse in either case? I have personally elected to go along with my adulteration of GM's instructions and install the fuse. This decision is based primarily on reports from other Owners that have installed the fuse without blowing anything up! As for the hapless GM owners with the TP2 option who have installed the fuse, kindly provide us with the address of your funeral home!

[SS396]

I am sure glad my installer didn't read the owners manual. I added the fuse and everything works fine. I sure wouldn't add more wires.

It's your decision, but I have no problems.

[AbqGeorge]

The warning is to NOT INSTALL the fuse if you have a GASOLINE ENGINE with the DUAL BATTERY OPTION.

Yeh, they worded it poorly.

On a Duramax with dual batteries put in the fuse!!! It provides the 12 volt battery charge line. It's interesting that the fuse for the brake line is already installed on STUD #2.

[Geo39]

AbqGeorge:

This, of course, still leaves us wondering "why" we should not install the fuse if we have a dual battery set-up with a gas engine! Remember the early computer instruction books? Some of those writers went to work for GM!

Geo39

[Snuffy18]

Geo39
I've found the whole towing wiring thing to be shrouded in mystery. I struggled with the same question about the fuse for my new 2003, and finally figured it out myself. The dealership was no help.
Let me ask you this - where did you get the harness to hook up your trailer brake controller? A friend with a 2002 found one in his glovebox. My dealer insisted I had to buy one ($50 or so) because it was optional. Sounds like BS to me.....

[FirstDiesel]

Snuffy

01 and 02's got a harness. 03's didn't and the harness is different so get theright one.