The Stovebolt Site Forums The Shop Area Interiors Heater Switch Location

All my 47-55 AD's have either no switch or an aftermarket one. Can someone please tell me exactly where the original 1950 heater switch was located?

I thought the heaters were a dealer add on...

Heaters were accessories that were added by the dealer, the owner, a friend, or a shop.

The Chevrolet Accessory Installation Manual shows where the parts for the Chevrolet accessory heaters are to be installed. 1951 Accessory Installation Manual - 1950 would have been similar.

I can't seem to find the exact hole the heater switch was located on the dash. There are several choices and I want to get this right. Best guess is somewhere on the left side of the steering column. Anyone have dash pics that would show the original heater switch?

There are at least three holes under the dash to the left of the steering column (and to the right of the parking brake release):

1. fog lamps switch
2. heater motor switch
3. deluxe heater (Air Flow - Fresh Air) - defrost (47-52) or fresh-air cable (53-55)

Do you you have an Accessories Installation Manual for your year truck?

I have 5 holes to choose from. The only clues I have are a completely stripped down cab. Should have taken better pictures 10 years ago. The picture here was taken before I welded the holes shut that didnt belong, but the 4 in a row with the one hole behind one of them is stock.

http://devestechnet.com/Images/Restorations/1950B/D50b01003lg.jpg

I verified by looking at one of Dads50 pics. The far left of course is parking brake release. Shots of a stock truck dash when its all populated would be nice. Thanks!

I do not have that one Tim. Never thought of it as an accessory until now.

Here you go.
https://www.flickr.com/photos/advance-design_parts_co/17037284497/in/album-72157651722976780/
Extremely low mileage fire truck example.
https://www.flickr.com/photos/advance-design_parts_co/15295057304/in/album-72157631870734114/

NIce, Brad.

I'd put the fog lamps switch between the cable pull and the parking brake pull.

Deve, if there are more holes than what is needed for the above items, just pick your holes - you now know the relative locations. That would most likely be more like to be "correct" than what a dealer might have done?

The hole with two, one right behind the other is for the defrost cable, if I remember right there is a stud and dtent for the bracket.

Fig 101 shows it right next to the defrost cable.
http://chevy.oldcarmanualproject.com/accessories/1951am/51aim38.htm
But I guess that would all depend on the type of heater that was installed

That sounds perfectly reasonable. I sincerely thank each of you for going to the trouble. It's especially important because the result will shape how we go about placing the 25 watt resistors that are suitable for upgrading to 12 volts. The original switch will not work over the long run with 12 volt heater motors unless we address the elephant in the room which is the 5 watt resistor that is sufficient for 6 volt but totally insufficient for twice the wattage. 12 volts needs a min of 14 watts.

The 6 volt motor using 12 volt power is still woefully insufficient but if you put the 12-6v reducer in the positive line between the BAT terminal of the switch and the positive power source, you can get away with it.

I am researching this problem on the bench using a test engine to generate the 13.8 volts necessary to really test this issue and the mathematically sound 25 watt power resistors that will reduce the heat to a manageable 175 degrees or less. I have an IR Thermometer to test and report those findings. There is no self evident thought process where the conclusion is expected, rather we just test the system and let the results dictate the solutions.

As it stands, the 6 volt motor using the 13.8 volt charging system that is the heart of our 12v system will bring the temperature to more than 375 degrees on LOW. This is about halved if it were a 6 volt power source which is what the GM engineers expected you would do. Understand the switch is not the issue. The 5 watt quad lead resistor (basically two resistors combined) is way too low of wattage to last with twice the voltage. You can read the data so far and make your own conclusions here:

http://devestechnet.com/Home/Native12VUpgrade#heatersystem

I have tons more testing to do, but one thing is certain, that 5 watt resistor isn't going to do the trick for a truck converted to 12 volts. So, where do we put this new resistor array? Since it has to be off board the switch due to size, do we make a small heat sink plate that mounts above the switch using its mounting lug and hide it directly under the dash? Or, do we extend the wires about 3.5 feet and mount those resistors inside the air stream of the heater itself? This is why its so important to know exactly where the switch is mounted. What is in the way?

These are very real issues for 12 volt conversions. The reason people think it's no big deal is because they don't use the switch on LOW very often. The day they do put it on low for more than about 10-15 minutes, then wonder why there is smoke and then no heater is rapidly approaching. Hopefully we can offer a solution soon. Thanks again!

I fine tuned the resistor values a bit today. I should have purchased stock in Resistor companies. Turns out for the 12v motor, 12 volt system that a 2.5 plus a 1.5 ohm on LOW, and just the 1.5 on MED is the best combination. I liked the sound of the motor and the fan output best at 6 volts, 9 volts and 12 volts. The heat on a 25 watt resistor is only 140 degrees. Still hot to touch, but not dangerous anymore.

I then took Hot Rod Lincoln and Steve H's advice and spent the day working on a special bracket that mounts inside the heater's air stream using two existing screws so it will not be possible to tell the mod has been made at all. The bracket is easily removable and will come complete with the resistors and wiring harness.

And, because I have been asked to do it, I am also testing a stock 6 volt motor using 12 volt source to see how it behaves using 2 - 10 watt (5 watts bigger than stock) resistors using the same bracket. I will also try the 12-6v reducer to report the differences in these solutions so you can make the call. This will hopefully stop that overheating issue and help explain why they get hot enough to fail using twice the voltage.

I like the rubber matt. Also wondering how you filled in the radio hole? Did you make that yourself?
Nice

You may have given me some thought on why I cant find a heater switch for my '55 3100. I have tried several with no luck. The last from a Volvo rheostat type but started smoking. Now I think I may have a 6v heater motor in the truck. Is there any way of finding out? Perhaps some way of knocking down the voltage to the motor?
After all the work on re-coring the heater itself I cant control the motor.

Visually, if the motor pretty much covers the entire hole on the firewall, as if it belongs there, chances are its the original motor. What you need is a switch like the one I pictured here:

http://devestechnet.com/Images/Projects/12VUpgrade/12VUpgrade0006lg.jpg

then a reducer like this one:

http://www.speedwaymotors.com/Voltage-Reducer-for-Fans-and-Motors,2375.html

put the reducer before the switch so it encompasses the entire circuit or you will have the same problem you have now.

If that works for you great. If not, that instruction I posted above will help you change to a 12v motor. Even if the heater is different, the motors are the same.

Deve,
I am not sure what you mean by "put the reducer before the switch". The reducer could go anywhere in the circuit.

Are you using conventional electron current flow terminology(arbitrary direction was selected when electricity first understood) or electron theory current flow terminology? Remember, according to electron theory, the electrons actually flow from the negative terminal of the battery to the positive, which means in our Chevys, with negative ground, the electrons actually are flowing from ground, through the accessory and then into the wires back to the positive terminal of the battery.

If I understand you correctly, if you are trying to "protect" the switch, then you would put the reducer between the motor and the switch.

In truth, the reducer just needs to be somewhere in the circuit, doesn't matter where. Perhaps I have misunderstood you.
Regards,
Kent

If it were just a switch you would be right, but the switch has the very inadequate 5 watt resistors on board. If you do not put the reducer between the Ignition Positive and the BAT terminal of the switch, you will not be giving those resistors the necessary Wattage drop that is necessary for them to run cool enough to not burn up. We talk about current and ohms a lot but we forget the Power formula. At least that's the last thing I think about.

The switch was made for 6 volt input so they put 5 watt resistors when 12 volts can generate as much as 14 watts. The flow from neg to pos is a given. But when the electrons hit that reducer is when the electrons slow down and voltage is reduced. This isn't my idea, its how it works on the bench. Hook it up both ways and watch what happens for yourself. If you still think it works the way you describe, I will be more than happy to change all of the text I have written on the subject after what I thought were thorough bench tests.

Hooked up with the reducer after the switch will get you about 100 degrees hotter on the resistors. They will last for a few years that way because of the sporadic way we use the switch, but those resistors are slowly dying.

Edit: I am not infallible. In fact, I have to stop and think before putting a diode in a circuit to remember which way it goes! Getting older sucks!

Deve,
With a given voltage, the current flow of a circuit depends on the cumulative resistance of the circuit which would be the sum of the resistance of the accessory (i.e. motor), reducer (which is a resistor), switch (and it's associated resistors in this case), wires, ground, etc. It doesn't matter where the reducer is in the circuit.
Also, I don't understand your reference to resistor wattage. I thought resistors were rated by Ohms. Of course, resistors produce heat (watts) when in use but this would depend on the voltage.
In lieu of a test bench I consulted an engineer and an electronics tech whose hobby is rebuilding auto tube radios and auto gauges.
Perhaps someone can clarify for me where I am in error. I, too am getting older and relying on classes I took 40+ years ago.
Regards
Kent

Understand that. The entire reason for putting the reducer where I suggest is heat. GM put 10 watt resistors in because they did it for 6 volts all the way through. When putting a 12v power source on it, those resistors will be twice as hot give or take. As I learned during the bench tests, the difference is about 100 degrees. The resistors (which looks like one, but its two), run about 230 degrees putting the reducer where I suggest, and 330 or so if you don't. Its far too high of temperature for them to survive. I am working on a two 25 watt resistor solution that will make it much less of a concern where you put the reducer.

Thanks Dave, very helpful. Abroad at the mo in West Africa (we Brits do get about) but will have a go if I can locate the parts.

I did some checking today and a good way to prove your switch needs to go into the circuit with the dropdown reducer resistor is to check voltage at the switch. With the fan on, if you get 12v or thereabouts at the switch, its overheating the resistors. With the reducer between the bat terminal of the switch and IGN, you will solve that problem. My only 6v motor is toast, so I have to find someone who will sell me a working one to do further tests, but that will ensure you have those fragile resistors properly wired for the winter.

Glad to help Eddie!

here's my layout. i drilled another hole and re-positioned the left side knob array so I had spacing between the switches

ALL switches are visible ... the two switches placed below @ center are for the heated seats.

http://s67.photobucket.com/user/1951otter/media/DSC00328.jpg.html?sort=6&o=358

the final shows the heater switch with a 'C' for climate ........ not choke
i have a 292 with a 4 barrel and no choke needed. the throttle was not needed either.
on the far left is a stock H/L switch, a double pull switch for the safety start and FOG lamp positions and
a wiper switch for the electric wipers i installed.

five LED lights for L/R turn signals,
high beam
oil pressure switch
alternator

so see how i made the switch fit the dash

http://s67.photobucket.com/user/1951otter/media/1A-1.jpg.html?sort=6&o=230

by using two different washers a flat stock bar, and a coupler to connect the knob to the switch posts installed because the switch needed to be moved away from the dash due to limited space.


http://s67.photobucket.com/user/1951otter/media/0A.jpg.html?sort=6&o=231

http://s67.photobucket.com/user/1951otter/media/IMG000.jpg.html?sort=6&o=228

i had to move it up and i also don't have an arkansas throttle so that position can be used for another knob when the time comes

http://s67.photobucket.com/user/1951otter/media/0732700-R1-050-23A.jpg.html?sort=6&o=194

Nice Jim! So what switch did you use? Very innovative!

.

i believe it was a Cole Hersee Rotary switch because i went to 12vdc w/ the 292 and alternator. many of my electrical is from Cole Hersee. their stuff is good quality and one had to be creative when fitting a newer designed anything in our old trucks. it turned out nice.


most of the chevy supply houses that offer us folks have cheap switches. i had a $44 H/L new vendor switch from a vendor that LITERALLY FELL APART IN MY HANDS as i installed it into my 51. so i wrote it up for all of us bolters and simply rebuilt my stock switch. it was made in china and failed.

http://www.elecdirect.com/catalog/cole-hersee-switches/cole-hersee-rotary-headlamp-switches

the reason you see the stock C choke turn switch is because i ground down and glued the C onto the black cole hersee knob so it appears stock.

i left the cole hersee knobs as stock on the wiper and safety START / FOG switch on the left side of the wheel

.
.
. junk headlight re-POP switch from chevy duty

https://www.stovebolt.com/ubbthreads/ubbthreads.php/topics/706910/NEW_repop_high_$$$__H/L_switch.html#Post706910

Classic Parts of America aka chevy duty sent a defective H/L switch.
hummmmmmm

they will re send a new one but the hassle is a hassle

after i installed it...... it did NOT WORK. I then did a simple continuity check x2, with my VOM and confirmed that the switch did NOT OPERATE CORRECTLY i called CP of A. then I went back outside to unwire / rewire my old switch, the NEW switch CAME COMPLETELY APART IN MY HANDS. the top plate lifted off exposing the guts and three small springs, the four fold over tabs are thin and apparently not bent over properely and this is their expensive switch @ $45.00.
first photo shows the swap, everything is going just fine. HEY it's a brand new part, i should not have to double check it @ 45bucks. i took the first to place in my photobucket site. pix
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=IMG_0715.jpg headscratch
second and rest of the photos show removal and when i got to the second screw removal the whole thing fell apart in my hands. :mad:
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=IMG_0716.jpg
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=IMG_0719.jpg
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=IMG_0720.jpg
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=IMG_0721.jpg
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=IMG_0722.jpg

HAS anyone else had a defective expensive 47-54 12V stock replacement H/L switch from these folks??

BE CAREFUL :mad: :mad:

i believe I'm going to buy a Cole Hersee H/L switch

jockbolter50 Offline

Loc: Scotland
Jim, I've still to investigate,but I suspect I have a defective switch.
I recently hooked up my new loom, followed the instructions to the letter and guess what,it doesn't appear to work.
Mine came from Truckandcarshop.com
Cheap ROC trash....
With the knob pulled out to full extension it flaps about terribly,I have no park,dip or main beams,plus the dimmer function doesn't work.
The rear park lights work fine.

What is this Cole Hersee switch? Care to expand?
_________________________


Jim, ask them why they except such junk from vendors..... and see if they tell you the same thing they told me over a piece of their junk...this is what they told me "we been selling this part for years and haven't had any problems"
Yet, I sent them a FEW post to show how my particular part was a piece of junk and they never responed anymore. That was two years ago...still no answer!! LOL

Cole Hersee is one of the manufacturers that a lot of OEM over the trucks use. Most Navistar part numbers are a Cole Hersee. They don't make reproductions, but they do make stuff that works. http://www.colehersee.com/catalog_top/index.htm However, after running over the road trucks for almost 47 years, I have seen my share of new defective parts.

I got a 6 volt motor working yesterday. Took it all apart and fixed the broken rivets and wire. The motor works great, but I am surprised at how many stock switches I have that are bad, NOT having to do with the resistor!

Anyway, all of the testing information is here:

http://devestechnet.com/Home/Native12VUpgrade#heatersystem

New content is in the big yellow box. I was getting about 240 degrees on the Reducer, but 350 degrees on the resistor on the switch. If I move the switch out of the reducer's influence and put it IGNITION-SWITCH-REDUCER-MOTOR, I got another 100 degrees on the already under-rated resistors. I shut that test down real fast. When you hear people complaining about how hot those resistors are, that at least points to the answer.