When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
working on a 03' f250 with a 6.0 , although this is not a 6.0 problem it is a strange one. The dash gauges stopped working and alt.was not charging. after looking at fuse location in owners manual, I got the multi-meter out and checked volts at each fuse. I found #46 blown ,although the manual shows this to be the left side low beam, the gauges and alt. began working , but it continues to blow fuse's at a whim! any one ever seen this
Are you absolutely sure that it's #46 you're looking at and not #45 (Ignition switch Run/Start feed)?
#45 is one of the fuses that powers the HEC (Instrument Cluster), among other things. The HEC is also responsible for sending power to the I circuit of the alternator. The I circuit is what switches the alternator on so it can start charging.
If it is #45, you have a short somewhere. Unfortunately that feed could run any number of things, so tracing down the short could be difficult. I'd guess it's somewhere under the dash though. A wire rubbed through against a frame member.
This diagram might help. It's everything that runs off of #45.
I didn't realize until I looked at the diagram, but #45 feeds the Tow/Haul switch. It is VERY common for the wires to rub through where they enter the shift lever, because of the regular movement there, and blow that fuse. I think the odds of that being the problem are high.
Thanks great info. I could swear it was # 46 , but was stuck in parking lot at the time. will check the # again in the morning,,, #45 makes more sense . Thanks again.