Any ideas? 2002 31B LD.
Thanks,
Mark
Does anyone have a electrical schematic for 2002 31B LD?
Does anyone have a electrical schematic for 2002 31B LD?
There is no such thing.
Can you tell me if there is a fuse for the alternator?
Mark-
Not charging the chassis battery, the house batteries, or both?
I assume if you're asking this question that you did not install the new alternator yourself. If so, then what does the person who installed it say about it not charging the chassis battery? I should think that was a functional check he would have made.
Check your owners manual. It likely has a diagram of the alternator/charging circuit. On coaches old enough to have a diode isolator installed, the alternator output cable goes to the center post on the isolator. The chassis battery 12V+ lead goes to one of the isolator output posts, and the house battery bank to the other output post. I believe later coaches used a solenoid, rather than a diode isolator. As I said, look in your manual.
Mark H
I am not a tech. There well might be a fuse for the alternator. Anything under the hood is Ford, not LD. Your Ford owners manual will show the location of each fuse. There is a box under the hood and also one under the dash. I hope you got both the Ford and LD manuals with your rig.
You did not say which battery is not being charged. If it's not charging the chassis battery, go back to where you had it installed. You can test if the voltage is reaching the house batteries with a VOM. Anything reading over 13 indicates voltage is reaching them. 14.2 would be about right. If you don't get a reading, you may need a tech. Good luck with that. most know less than I do.
Charging the house batteries with the alternator is a slow process.
The alternator is protected by a fusable link.
It's a short section of calibrated wire, normally 4-gauge sizes smaller than than the wire it is protecting.
If it burns out, it needs to be cut out and then have a new usable link splice in.
If the alternator is protecting good power, chance are the isolator had failed.
With the engine running, check all three terminals of the isolator for voltage.
You should see readings in the 13-volt range, on all three terminals.
Larry
Did you mean fusible link, Larry?
Larry means a fusable link.
Ford put the big one at the starter solenoid end of alternator output/ ammeter shunt cable in 1991.
LD may have relocated it to accommodate the battery isolator.
My 1991Coachman Van was electrically dead whhen that one melted, well blew, Not even the 4 way flashers would work. Cause, the alternator diode board disentgrated shorting the battery to ground.
Thanks for the great advise. We will be rechecking the system Monday.
Electrical issues can be the most frustrating and difficult problems to solve.
Mark.
I will be ordering an owner's manual next week.
Mark-
The Ford EVTM (Electrical and Vacuum Troubleshooting Manual) went with the LD when we sold it a couple years ago. They are specific to the model year of the chassis. You can pick them up on eBay for not a lot of money. The EVTM covers all the Ford wiring, including the ignition and chassis battery charging systems.
Here's the diagram from the 1997 LD manual. It covers the connections to the diode isolator and from there to the house batteries.
Mark H