View original topic: Heating FAQs - BN4 Gas heaters & heating related topics Page: Previous  1, 2, 3, 4, 5
Serpent7 Sat Feb 04, 2017 12:57 pm

I have a 73 Vw Thing, and when I purchased it all the heater parts have been removed. I tried contacting the previous owner to see why all the heater stuff had been removed. How hard and expensive will it be to locate and reinstall everything? I know it's a very general question but it a possible thing to do without getting screwed?
Your thoughts?

notchboy Sat Feb 04, 2017 1:34 pm

Yes its entirely possible to do.

Weather you do it piece by piece or most all at once it for sure can be done. Last year - and this is not a common thing but two complete units poped up in the box NOS condition.

I got one of them here -

These will fetch in the $500 to even $1000 foe the ambitious. Those listed pics will also aid you in seeing the complete unit and parts - less the cabin ducts.

It may take some diligence but all the stuff is out there. Look for parted Thighs with gas heaters, Ask the seller to pull everything for it.

There are also plenty of "fixit" info here and you tube so you can restore one or three.

I myself have lots of vids and an ongoing thread over in the Bay forum.

notchboy Fri Feb 24, 2017 2:16 pm

Ive had a space dedicated to the Eberspacher made up. All types of Eberspachers welcome!

notchboy Mon May 29, 2017 4:39 pm


vwwestyman Wed Sep 06, 2017 12:13 pm

I was excited that I got my heater to work again over the weekend! It had quite heating some time last fall and I didn't bother to figure out just why. (It didn't seem to be firing at that time, the fan was running but no fire and eventually it timed out.)

I got it working by cleaning up all the electrical contacts. I had been working on the contacts in the fuse area and got inspired to give that a shot.

So it worked great for a few days.

Then yesterday while driving it made a squeaking noise a couple times. They were very brief the first two times, and I actually thought it was the speedometer getting cranky.

But the third time it made the noise, I was at a stop light and quickly realized that was the heater. Before I could turn it off, though, it quit altogether. No fan run on or anything.

I haven't had a chance to check the safety fuse or the "breaker" or any of that on the heater yet.

Just wondering though, what the noise may have been and where to start.

While I was at the light, I did briefly reach in and see if the air fan moved and it does still spin.

notchboy Wed Sep 06, 2017 12:38 pm

There are only two moving parts - the fan and the pump. Most likely the fan pooped out. The combustion side lives in a harsh environment.

notchboy Fri Mar 08, 2019 3:38 pm

Stickers available.

kenj06 Sun May 05, 2019 7:37 pm

OK BN4 experts, I'm looking for suggestions to resolve my issue.
The heater works fine during startup, cycles through combustion and cool down and shut down fine.
The problem is at night when I have the lights on, and the heater is NOT in the combustion cycle, the lights dim and the fan slows, in time with what would be the fuel pump pulsing. But the fuel pump is not working at that point in time. It's almost like there is a short during that time but no blown fuses or burnt wires. Even without lights on, I can hear the fan pulsing. During the combustion cycle, when the pump is pulsing, no lights dimming and fan speed is steady. During Shutdown, no pulsing.
Engine speed does not make a difference on the pulsing. I can be at a stop light or on the highway and the lights dim just the same.
The charging circuit (generator) checks fine, 12.8V out of the regulator at idle and 13.8 about 1500 RPM.
I cleaned the grounds (battery, battery to body, chassis to tranny and heater). Cleaned all the connections on the charging circuit. Cleaned all the terminals on the switch and those I could reach on the heater, without taking it out. Took the pump out and cleaned it and checked it. Measures 6 ohms so pulling around 2A which seems normal.
This would make sense to me if it happened when the pump was running.
It's been this way a few years and I would like to get it fixed so as not to attract the attention of law enforcement during chilly nights because my lights are pulsing. I'm used to driving cold VWs but the other 1/2 likes the heat. :)
My next step is to pull the heater over the summer, tear it down and clean it up.
Any suggestions on where to look? Maybe a bad capacitor/condenser, relay or?

notchboy Sun May 05, 2019 8:23 pm

Generator or alternator? VW put 75 amp alts in later bays with the metering type BN4 & BA6 gas heaters. The only time I hear this kind of issue is not enough amps or the voltage drops below 11.5. I just bench tested a later metering pump BN2 and the pump kept stopping during ignition cycle. Put the trickle charger on then - bam enough juice, ran fine.

kenj06 Mon May 06, 2019 7:05 pm

notchboy wrote: Generator or alternator? VW put 75 amp alts in later bays with the metering type BN4 & BA6 gas heaters. The only time I hear this kind of issue is not enough amps or the voltage drops below 11.5.
Generator. Measured voltage at the heater and have 11.5 with no lights, 10.5 with lights. Voltage drop somewhere in the 45 year old wiring, imagine that. :roll: Now to find it.
Thanks for the tip!

notchboy Fri May 24, 2019 9:28 pm

Picked up some Eberspacher goodies. Ill be selling the Thing thermostats with cables for $180 ea if anyone is interested.

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