TheSamba.com :: View topic - Help! Trying to figure out the wiring on a BN4 Heater!

Fri Nov 24, 2006 7:20 pm

I recently bought a BN4 heater on ebay. I am trying to figure out what wires go to what. I have looked at the wiring diagrams available on various other sites, but none seem to match it exactly.

Here is what I have. First there is the red wire and the grey wire. I know that the red is the 12V source and I believe the grey one goes to the switch. Next there is the hot green wire and the brown one with the stripe. I know these go to the fuel pump. There is solid brown wire that is in the same bundle as the fuel pump wires but is much longer. Is this a ground wire? It seems that all of the brown ones are.

The two wires that really get me are the ones on top near the output end of the heater. They are both blue and I cannot figure out what they should connect to. One of them goes directly into the relay under the cover.

I really appreciate any help anyone can offer. If anyone needs pictures, I can post some. Thanks.

Fri Nov 24, 2006 9:14 pm

I believe the 3rd wire connects to the fuel tank sending unit. I recently replaced the wires to the heater pump on my Thing and I remember the fuel tank wire being included on the same plug.

Sat Nov 25, 2006 9:32 am

Thanks. Any idea what the blue ones are for?

Also, I forgot to mention that I am actually installing this into a 66 beetle, so there is no fuel tank sending unit. Can the extra wire be connected to something else, or will it work if I leave it disconnected?

Thanks for the help.

Sat Nov 25, 2006 4:56 pm

The blue wires connect to the thermostate. On a Thing heater, the thermostat is located on the elbow on the "hot" end of the heater and is controlled by a push/pull cable on the dash.

As for the tank sending unit wire, you won't need it for anything. It's only a ground wire for the fuel guage.

Good luck...

Sun Nov 26, 2006 8:41 am

Thanks a lot. I do not have that elbow with the thermostat so that is why I couldn't figure out where they went. I'll have to see if I can find one.

Again, thanks for the help. Maybe now I can get this heater fired up.