Ford E450 chassis Electric Trouble

[bair]

While upgrading our house battery from a single 12v to 2 six volt batteries we inadvertently crossed the polarity. By the time our error was noticed we had burned up the altonator (we actually tried to start it). We did not notice at the time but now there is no power to the radio, gauges, power windows, CIG lighter, and cabin lights. The door locks work as well as the horn. All of the engine systems seem to work as there are no error codes. I've verified all the relays in both fuse boxes and both auxiliary relay boxes test correct. The fusable links to the altonator are intact. I'm not sure what is left to do but start tracing all the wires to the systems that are dead.
Does anyone have any ideas.

[enblethen]

Sides are determined when sitting in driver's seat. Right side is passenger, left side is driver's side. Of course this is in most countries with the steering wheel on the left side.
OP: Glad you found your problem!

[gmctoyman]

One comment, or question. Which is the left or right side of the engine ? It would be nice to use driver side or passenger side....or Port and Starboard.

[bair]

FOUND IT! a fuse that I looked at at least 3 times. My wife even remembers looking at fuse 22 and even testing with a Ohm meeter.
Again thanks for your help. I had almost given up and call to tow the coach to so a local shop. it would have cost a small fortune for a simple problem.

[enblethen]

Normal Ford starter relay is not in a box but mounted in the open.
Are you confusing battery disconnect or charge relay with starter safety relay?

[bair]

first thanks for the help. I've subscribed to alldatadiy.com for diagrams and diognostic help. there is voltage on either side of both links. the one that looks melted is in line directly to the altonator/generator.this has an additoinal small brown fusable link it's a 12amp as well. there is good voltage on either side of both circuts 12.7 with the eigine off 14.35 with it running. On my 2006 the starter relay is a component in the battery junction box. the diagram you have is acurate. the line in yellow runs under the battery tray where the yellow fusable links are and up between the top of the radiator and it's support and across to the battery junction box. there is the same voltage at the battery junction box as noted above and when test with a simple Ohm meter there is no resistance or the circuit is open. The fuses in the battery junction box show the same voltage as noted with the exception that some fuses are not supposed to be hot unless the engnine is running or ingnition is to accy.
I'm about to test the voltage on the fuses at the central junction box which is at the drives feet. i had already looked at all of these fuses and they were good.
I looked all over for a ring terminal with no wire, but since the starter relay is a component in the junction box I'm not sure it applies.
Again thanks for your help.

[enblethen]

If you have no resistance then they are open.
Resistance check would be from the relay side of the fuse link to a clean exposed wire on the rig side.
Yes, they could be bad.
I would be nervous to see any type of melted insulation.
You checked the fuse links for voltage on the rig side?
There could be another wire dangling that has come completely into. Look real close! Look on relay terminal for a ring terminal that has no wire connected to it.

[bair]

The coach is a 2007 model with the chassis being 2006. I've inspected the five fusable links shown in the diagram. The two yellow 12 guage links that feed the fuel pump and blower motor relays and the battery junction box look brand new and there is no voltage drop between the battery and the junction box. One of the grey ones that are between the battery and generator has the insulation melted but again there is no voltage drop. I also checked both circuits with an Ohm meter and there was no resistance. I'm not an electrician by any means but this seemed normal. Is it possible that even though I'm not seeing any loss of voltage or reading any resistance that these fusable links may be the cause of my problem? I had asumed that since the system seems normal to the junction box, the problem is either in the wiring or fuses after that point or each component that has no power is actually dead. Either way it sounds like a lot of wire by wire testing.

[Tom_M1]

You don't say what year your coach is, but on my 2005 there are several fusible links. Hopefully this diagram will display okay.

[bair]

enblethen wrote:
Look under the hood behind the battery, there should a start relay. On the battery side should be a couple large fuses in protective covers. Should be three or four inches from the relay.

Thanksfor the help. I'm out of town for the weekend and will definitely check when I get back. I thought I inspected that area. Are you referring to the two yellow 12 gauge fusable links? I don't remember seeing anything else.

[enblethen]

Look under the hood behind the battery, there should a start relay. On the battery side should be a couple large fuses in protective covers. Should be three or four inches from the relay.