Electrical Gremlin Chassis Charging

[Born2Travel]

I have a 99 P30 chassis with a 7.4 engine.

When we were ready to depart our summer gig I noticed the alternator wasn't alternating and it failed the battery disconnect test. To get to our summer gig we drove to the middle of no where an turned left for another 45 miles. So, needless to say trying to get a new part was a thrill. We were able to get the old alternator rebuilt. When I installed it I noticed the dash voltage gauge wasn't reading anything. The alternator passed the battery disconnect so we headed home. When I would engage the emergency start switch the gauge would read the charge with enough voltage to indicate the alternator was in fact alternating. I put a load on the coach batteries (no shore power or generator on) and the alternator charges the coach batteries back up. Once home I stared at the thing and that didn't fix it.

So far, I have had the alternator tested at two places and it passed. The batteries are holding a charge but the chassis battery doesn't seem to be taking a charge from the alternator and the gauge is dead unless the coach batteries are engaged. The battery isolators seem to be doing their thing and the ground is clean and grounding, and all battery terminals have been cleaned. I can't find a fusible link between anywhere. Please note I didn't say there wasn't one - I just can't find one.

Before I start chasing the gremlin, with great vigor, I want to make sure there isn't something simple I am missing. Luckily I have until spring to catch the little dickens. Any direction would be most appreciated.

 

[Born2Travel]

Found the problem. There was a double secret hidden fuse that was the culprit.

 

[Gary RV_Wizard]

Unusual to have a fuse in the chassis battery charging circuit, isn't it?  Is this a Ford F53 chassis or Chevy P30?

 

[Alfa38User]

Might have been that otherwise almost invisible "Fusible link"!!

 

[Born2Travel]

I was at wits end by the time I posted the query. I knew the charging system was charging it was a case of the gauge not showing anything unless the switch was activated showing the coach batteries. That ruled out a bad gauge. I reread my original post and it should have read the chassis battery does seem to be charging but the gauge doesn't work.

I never found the almost invisible fusible link and think it is in the unicorn, bigfoot, government is here to help us category. The "instrument panel" spot in the fuse block was empty. GM had told me to test that fuse!!! My "plan" was start at the alternator and work backwards and see if the wires were broken. So I diligently followed a pink wire to a harness where it met up with about a half a dozen other pink wires. A few adult beverages later and on the next to last wire I found an inline fuse holder almost at the fuse block. it was above the block mingling with other wires. Had I not been following the other wires I'd have never found it. The fuse was blown. Sometimes one wonders what builders are thinking. They had tied the leveler indicators, a power supply and the voltage gauge (and who knows what else) on the same circuit for some reason. I am still fussy on why they didn't leave the fuse in the block.

The simplest things can make a sane man get gray hair and drink.