73 Thing-gas heater

[email protected] · Posted: Fri Mar 27, 2009 5:57 am Post subject: 73 Thing-gas heater

A deservedly belabored topic. The Gas Heater-a wonderful device sometimes:
I need help with a wiring issue: From the timer switch ther is a "pigtail" or harness which runs through the firewall and plugs into the heater. In addition to the plug there are 3 more longer wires. 2 of these connect to the fuel pump the 3rd one is brown, just a long as the fuel pump wires with an uninsulated female half of a spade connector on it. I looks ike it was meant to run to a location in the vicinity of the fuel pump. Where does this brown wire connect-is it a ground wire-my manual diagrams a brown wire as a ground. (There is also a short brown wire with an "o" connector that comes out of the heater itself I know this is a ground.) Where does the long brown wire connect to? Any help would be appreciated.

Grandpa Paul

'73 Thing
'49 Ford F1-pure st. rod
'74 Lancruiser V8/Overdrive conversion

Emeritusx · Posted: Fri Mar 27, 2009 10:24 pm Post subject: Re: 73 Thing-gas heater

[email protected] · Posted: Sat Mar 28, 2009 6:06 am Post subject:

Thanks, photos would be nice. I tore into the dash yesterday and the end of this brown wire that is in the dash is grounded to the dash itself.
the wire is bundled with the other wires coming out of the timer switch and runs into the trunk. It is a part of the actual harness from the timing switch but not conntected to the plug. It is about the same length as the fuel pump wires. I have 2 timers and 2 sets of wires. On the set that is in the car the wire was cut when the heater was removed. I have that heater too but cannot find the end which was cut on the heater. On the other set of wires it is in tact. As it is grounded on 1 end it must go to something which needs to be grounded.

Emeritusx · Posted: Sat Mar 28, 2009 7:53 am Post subject:

My Camera really sucks. I tried seven different shots. Need more light. Soooo I drew one instead:

Image may have been reduced in size. Click image to view fullscreen.

I only have one set of wires from the dash, the long half go to the gas gauge sender the other two (red and brown) go to the heater (red to red for orientation)

If you need more ask.. If the sun comes out maybe I can get some good photos, however I know there are a bunch here already, as I went thru 'em all to get my heater working
_________________
82 Westy ☢, 66 Splitty ☮, 73 Type 181 ✠

[email protected] · Posted: Sat Mar 28, 2009 9:09 am Post subject:

Thanks-among other things, I walk a lot-small town, old age and all, (it also is a time to think and solve the worlds problems.) It occured to me this morning on one of my walks that there is already a brown wire coming out of the heater to ground and inside the heater this wire is split to several locations. When I connected the heater ground wire to its location on the trunk floor there was a, non-stock-ground to the fuel tank sender in that same location. Could the wire in question be the proper ground for the fuel tank? I had only one wire running from the sending unit to the back of the speedo, through he same location as the heater wires. It also occured to me that there is nothing else in the front of the car but the heater and the sending unit that would need grounding. In my thinking about this I swore that once the riddle was solved it would be something so simple as to make me realize for the millionth time what a dork I am.
YOUR DIAGRAM AND EXPLANATION WERE OUTSTANDING IN HELPING ME TO SOLVE THIS PROBLEM. Your explanation of the wires going to the fuel fuel tank sender and the fact that I only have 1 wire from the dash plus the home made ground at the sender proved to me, again-I am truly a ding dong. Of course the proof will be in the testing of the heater. Today, I am going to test the pump and plumb it into the fuel system and spark it up. I'll let you know what happens-may not get it done til tomorrow or Monday.

Thanks again

Paul

Thing-Rod-Cruiser

[email protected] · Posted: Sat Mar 28, 2009 3:55 pm Post subject:

I got the old heater out and the new one in and wired. I tested the pump before I installed it, had to whack it a couple of times. It would "clack" each time I touched my leads to it so I assume was working. I installed it, plumbed it all and turned it on. Everything works except the pump. I buzzes at the blower, (blows really well and quiet), but the pump does not clack. I tested the wires at the pump, each by itself and then grounded one to the other and got no light on my tester. What I've got now is cold air but 1000% better than before. I will resolve the pup problem, I have no doubt. Thanks for your help-the diagram was great.

Emeritusx · Posted: Sat Mar 28, 2009 4:21 pm Post subject:

Cool, to get gas flowing in mine I blew thru the hose and turned it on (it clicks all the time whether pumping or not, and gas actually started flowing, very little, but enough to run the heater.

My fuel pump works intermittently now. But man when it is working. HEAT!

Kinda strange to get cooked out of a Vdub...

I now about the walks, I am one of the few here that is older then my bus.
_________________
82 Westy ☢, 66 Splitty ☮, 73 Type 181 ✠

Emeritusx · Posted: Sat Mar 28, 2009 4:25 pm Post subject:

BTW The gas tank sending unit should have it's own spade lug for your ground wire in the bundle from the dash. The heater ground was the hole in the trunk (little philips screw)
_________________
82 Westy ☢, 66 Splitty ☮, 73 Type 181 ✠

thinghunter · Posted: Sat Mar 28, 2009 5:05 pm Post subject:

Once after changing my fuel line to the heater I had to take the line loose from the heater, take the wires loose from the fuel pump and use some jumper wires from the pump to a spare 12V battery. I then tapped the wires to the battery rapidly until gas came out the hose. I put everything back together and it has worked every since with no problems.

The pump is a pulse pump, if you just left current going to it after 1 pump it wouldn't go again. This is because it is somehow controlled by the speed of the heater sending a pulse down to the pump so the fuel is pumped at the rate the heater needs it.

[email protected] · Posted: Sat Mar 28, 2009 6:00 pm Post subject:

I will try goosing it with a spare battery. The pulse thing makes sense. It may have clicked once when I would turn it on but did not continue after that. I will "bump" it with the battery until fuel begins to come out.
This is my 4th gas heater. I've onlu had trouble with one previously, in a thing, in a snow storm no less-minutes later the wipers quit too.
Gar heaters are outrageous in VWs. One of mine, years ago was in a 1963 panel, it was in the engine compartment but it cooked-almost like being in a real car.

To the old guy: I'm way older than you 66 bus. I had one, in '68, I loved it. I've loved all my VWs. I havent had one since '01, (sold 8 in 1 week) I'm glad to have another-a thing no less.

Thanks for all the help.

Paul

FlowerPowered · Posted: Sat Mar 28, 2009 6:15 pm Post subject: Mystery brown wire

All the BROWN wires in the heater system eventually will connect to chassis GROUND. Three of them tie together at pin 31 of the control relay J8; the largest gauge brown wire is sized 2.5mm (about 10 AWG) and should be routed directly to the chassis; the others are smaller 1.5mm (about 16 AWG), one should be connected to the metal case of the heater and the other to the negative side on the blower motor. There is another brown wire off the timer connector pin 31 which should go directly to chassis; it provides the ground only for the green warning light inside the timer knob to illuminate when the park/head lights are also turned on.

FlowerPowered · Posted: Sat Mar 28, 2009 6:51 pm Post subject: Fuel pump operation

The fuel pump operates by pulses from a contact on the heater blower. The contact mechanism is geared down so that there is a pulse sent to the pump on every 33rd revolution of the shaft. The pump itself works like a relay, not a motor. Therefore applying a constant voltage to the fuel pump only produces a single throw of the pump piston.

Daddie O · Posted: Sat Mar 28, 2009 10:44 pm Post subject:

The fan on the heater spins and that makes the points inside the heater open and close, when closed it completes the circuit and sends the "pulse" of electricity to the fuel pump. Use a multimeter or continuity tester at the fuel pump to see if it is getting 12volts on and off. The fuel pump will go tic tic tic tic tic as it gets pulses of electricity. If you are getting pulses at the pump but the pump isn't pumping give it a few whacks. I had to whack on my fuel pump every day for about a month till it started working regularly without whacking on it. All this is after Ian and I disassembled the heater, adjusted the points and put it all back together (since mine wasn't getting pulses at the fuel pump.

man130 · Posted: Sun Mar 29, 2009 8:41 am Post subject:

Question -to check the pump for 12 volt pulse,do I just connect a multimeter to the two wires at pump ,while ingnition is on position,with timer switch cranked on w/temp control pulled out.If this is done I should read 12 volts on,12 volts off as the pump pulsates from the spinning fan.Am I correct with how I'm going to check it?There is no seperate switch to turn fan on, correct ,it goes on w/ either timer control or temp switch?My wiring seems a little funny for I have two keyed ignition switches,one in column, one in dash.Supposedly for towing behind RV the PO could unlock steering without worrying about power going to distributor,but some wires are still controlled by column some by dash/ NIGHTMARE.Imagine someone not knowing ,car is running but column key off,means steering locked starts to drive away....surprised ya think

Ian Epperson · Posted: Sun Mar 29, 2009 10:36 am Post subject:

[email protected] · Posted: Sun Mar 29, 2009 10:52 am Post subject:

This morning, after my walk, (Emeritusx-the walk does indeed solve the worlds problems), the only logical thing I could think of was that there was no power getting to the pump. I also smelled a little gas when I walked out the back door so I raised the front, took off the wheels and blocked it up. Then I pulled the wiring cover off of the heater. The fuse in tthe circuit that provides power to the pump, (light yellow and green wire), looked good but old. With the heater on, there was power on the yellow side of the fuse but none on the green side-the side that goes to the pump. I pulled the fuse, pinched the tabs a little and put a new fuse in. Turned on the heater, there was power on both sides and when I stuck my head under the fender there was a real nice, strong clicking coming from the pump. I got in the cab and in about 30 seconds felt hot heat coming from the outlet. I let it run for awhile then shut off and it shut down after a run down period. I had forgotten how nice the gas heaters were. It was, again, something so simple. How nice to have the heater working.
Thanks to all of y'all for the input, I know a lot more about theese heaters now both from you advice and research.

Paul

Ian Epperson · Posted: Sun Mar 29, 2009 12:16 pm Post subject:

Congratulations!

The most common reason for that fuse to have blown is an overtemp. If the thermostat doesn't move fast enough to shut down the heater, when the heater reaches 300 degrees, an internal device will short out the heater and blow that fuse. The 35 year old thermostats are often not moving fast enough. I'd suggest carrying a couple of spare fuses and be prepared for it.

You can tell when the thermostat is working because it will shut off the pump when it comes up to temperature, then turn it back on when it cools a bit - all the while leaving the fan spinning.

I have had a thermostat work fine for some time (like, 30 minutes) then misbehave and blow the fuse. One of these days, I'll finish my project of building a solid state thermostat for the heater.
_________________
VW-181 shirts and stickers.
http://ian.epperson.com/vw

[email protected] · Posted: Sun Mar 29, 2009 4:22 pm Post subject:

I carry a container of spare fuses in all my older vehicles. In this case the fuse was not blown, I think that the to contacts were dirty and the fuse was also loose between the. I was lazy and did not rebuild the entire fuel delivery system, just plumbed the T and lines to the pump. In order to solve my gas seepage problem, I took it all apart and replace all of the delivery system. Jeez, how many times to I have to learn that lesson-do it right and you only gotta do it once.

The assistance was invaluable.

man130 · Posted: Mon Mar 30, 2009 11:34 am Post subject:

Still playing w/ heater can anyone figure why someone would connect these two red wires to heater,one is fused one is not both about 3 feet long and not connected.They become live when heater timer is turned on.They are connected to first terminal left and right side.Any help would be great
[

Ian Epperson · Posted: Mon Mar 30, 2009 12:16 pm Post subject:

So, that heater has definitely been modified. I'd be very worried about it. Those two wires are attaching to where the 300 degree thermal cutoff switch lives (the black/silver box between the two circles) - it may have been bypassed. I also don't see the fuse holder that the switch is supposed to be rigged to. It could be that someone modified it to use a modern style fuse, but it's hard to say.

Very Sketchy.
_________________
VW-181 shirts and stickers.
http://ian.epperson.com/vw


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