I'm looking for power for an aux fuel tank's fuel pump that's only hot w/switch on. I have it hooked to the post on the fuse box for now and manually turning pump off. It's computer controlled but I don't trust it.
I also have an additional fuel gauge and looking at how to connect the light in it to the dash lights.
I also posted the question on the 5th wheel wiring thread because I saw where Shasta looks like he has the solution.
As always, thanks guys.

In the footwell on the drivers side, under the dash is the Miscellaneous Bussed Electrical Centre (MBEC). Its right behind the ebrake pedal where your trailer brake controller plugs in. In there, there are 2 upfitter connectors, one cell phone connector and one SEO connector. Each has switched 12V sources, I took the SEO connector for mine. Go to www.gmupfitter.com (http://www.gmupfitter.com) and you'll be able to download a manual that will show you the wiring pinouts and where to connect them.

Thanks skleppy for the info. I checked the pins and some are hot w/ ign. only. I went to the upfitter link and found that my '08 has an accessory harness under the dash near the center with 2-21 amp circuits. Each has a switched and non switched wire set. I'll try to locate it tomorrow since it's specificly for added accessories.

Does anyone know where the connectors for the MBEC can be purchased? I am particuarly interstested in the one that fits the SEO connector. Any help would be appreciated.

Can someone clarify what and where the SEO connector is in the MBEC? Is it one of the small pins where it looks like a plug should be? I looked at the upfitter website and found info on an accessory harness but I haven't found it yet. That would be nice, if it exists. I see guys using the pins in the MBEC to excite a relay with main power coming from under hood.
Has GM actually made it that difficult to add accessories or am I missing a really simple solution?

I can't remember what connector that I used, I'll check later on. I bought my connector from partszoneonline. The same connector was nearly three times the price on the side of the border. I know that the part numbers listed in the manuals on gmupfitter are not correct. When I took those numbers to the dealership here he could not cross them. The part number for the SEO connector is on the site here, just search for it.

Captjohn,

For my battery isolation installation I used the blue wire described in this bulletin, and passed the wire through the grommet on the left side of the fire wall to the isolator. It is a blunt cut wire, ignition hot. I just spliced it with a butt connector. I didn't use the SEO connection at all.

HTH

Captjohn,

For my battery isolation installation I used the blue wire described in this bulletin, and passed the wire through the grommet on the left side of the fire wall to the isolator. It is a blunt cut wire, ignition hot. I just spliced it with a butt connector. I didn't use the SEO connection at all.

HTH

That's the harness I'm looking for. I've looked for it but I guess I haven't looked hard enough. :o: I'll look some more tommorrow.
Thanks everyone. I'll let you know the outcome.