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1978 416 L DOKA
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Discussion Starter #1
I am a little stumped on this and have not really found an answer to this question. Any info would be great guys and thanks.

I have a 1978 416L with a heated windshield, the manual states to use both sides at the same time to prevent thermal issues with the glass. My switches will light up and provide power to the left and right side but when i pull both switches at the same time the power cuts out. This window was just put in and i have no idea if its a 12V or 24V.

- Is there 24 or 12 Volt versions?
- I dont have a reading yet on the watts or volts going to each side but does anyone have a reading off a working unit so i can compare mine.
- I am also looking for a correct wiring diagram just in case there might be a relay im missing that doesnt work.

Thanks again for any help.

Robert
 

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There are 12 and 24 volt variations. 12 have been really rare for a while now so that may increase the chance that yours is 24. I'm not sure how to tell. Maybe there is a part number stamped in the corner. I'm also not sure how to make a 24 volt work with a 12v system but there must be a way.
 

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'76 1300L,HE351CW,H15P Winches,Konis,Hydraulics,All Gears,10mm Plungers,Aftercooler,Lots of Littles
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Check the resistance of the two loops, it sounds like they have it wired so that the common ground (both sides of the windsheild share a the same ground tab).

C.
 

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1978 416 L DOKA
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Discussion Starter #4
Check the resistance of the two loops, it sounds like they have it wired so that the common ground (both sides of the windsheild share a the same ground tab).

C.
You are correct, there is three prongs. The middle being ground for both and the other two for power. How would this cause both to not work in your opinion? (my electrical skills are lacking so excuse me if this sounds stupid)


Robert
 

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'88 U-1300L, '70 406, '78 406, '78 416 project, '82 406, '57 404, '65 404, '70 404, '68 Haflinger.
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I may be totally wrong but seem to remember that the windshields are the same for 24v and 12v. The two legs are seriesed for 24v and paralleled for 12v. On 24v the middle terminal would float (no connection). If that's the case, the truck wiring determines if the windshield gets 12 or 24. That scenario would certainly make sense from supply standpoint and for why there would be two halves but warning not to use them separately.

Bob


Robert[/QUOTE]
 

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1978 416 L DOKA
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Discussion Starter #7
I have been digging for a few hours today and found a few other threads on this. Sounds like my truck might have a 24V installed and thats why both sides of the power turn off when both switches are on. I might need to find a 12/24v invertor to make this windshield to work. :crybaby2:
 

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'76 1300L,HE351CW,H15P Winches,Konis,Hydraulics,All Gears,10mm Plungers,Aftercooler,Lots of Littles
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Sorry if I am dense, but just to be clear you have a 12V truck and are thinking you have a 24V windscreen, correct?

C.
 

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1978 416 L DOKA
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Discussion Starter #9
No worries, i may not have stated that correctly.

My truck is a 12v vehicle that had a broken winshield, Scott at E.I. put a new/used window in for me but it doesnt work. I referenced the part numbers some time back with Steve at Eurotruck and was told it was the 24v version. My truck was origianlly a 12v windshield.

Sourcing these seem to be next to impossible so i thought the best/cheapest wasy was to maybe put in an invertor to bump it up to 24v just for the windshield.
 

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'76 1300L,HE351CW,H15P Winches,Konis,Hydraulics,All Gears,10mm Plungers,Aftercooler,Lots of Littles
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Make sure both sides are wired separately, 12Vdc to the 2 independent terminal, ground to the center.

Just double check....

C.
 

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1978 416 L DOKA
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Discussion Starter #11
I talked with Steve at Eurotruck again and from what he can tell the 12V versions were fazed out with standard glass.

The only option available now is the 24v version. Steve gave me a drawing for both versions. (which is the same) Looks like the only difference to me the windshields were wired differently.

My next course of action is to find the wire from the fuse box and wire in a 12/24 v step up convertor. Here is a link, any ideas?

Newegg.com - 12V to 24V 3A 72W Voltage Booster Power DC Converter Step Up Regulator
 

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1985 416 DOKA mid-mounted Rotzler winch, 1984 U1200AG
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Alaskan_IB,

I am very interested in how this works for you!

I have a heated windshield 24 volt and no wiring yet installed for it. I was going to change my alternator to a dual output 12/24 Volt system and use 24 Volts to run heating accessories and perhaps some lights.

I could not find as cost effective of a step up converter as what you have found. It will be interested to see if it can run the windshield heat or if you need two of them one for each side of the windshield.

I may change plans depending on your results.
 

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1978 416 L DOKA
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Discussion Starter #13
It states to heat both initially at the same time to prevent a thermal differential from cracking the windshield. Why they ever put in two switches I wont ever be able to figure out.

Those sneaky little German engineers are probably laughing right now! "Two switches....ha ha ha, ya press them both Hon's!"
 

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1971 Unimog 406 Agri Spec, Werner 530 PTO Winch
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The only difference between a 24V and a 12V screen should be the resistance of the two halves of the screen, otherwise a 24V screen will consume twice the power of a 12V and theoretically run twice as hot. It would make total sense that of the three terminals, one heater is wired left terminal to centre terminal, and the other centre to right. On a 24V screen you just connect left and right terminals, and on a 12V left to centre (being a common ground) and the other right to centre. Best way to check is to get a multi-meter set on the resistance ohms setting and measure the resistance between each terminal. I expect they will be very low resistances.

If you have a 24V screen and run it from 12V then it will just run cooler (approx half the temperature when running at 24V).

I will check with one of the maufacturers we use to see what resistances to expect and get back to you (we fit them to boats).
 

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1983 U1200 (parted out), 1979 U1700L
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The only difference between a 24V and a 12V screen should be the resistance of the two halves of the screen, otherwise a 24V screen will consume twice the power of a 12V and theoretically run twice as hot. It would make total sense that of the three terminals, one heater is wired left terminal to centre terminal, and the other centre to right. On a 24V screen you just connect left and right terminals, and on a 12V left to centre (being a common ground) and the other right to centre. Best way to check is to get a multi-meter set on the resistance ohms setting and measure the resistance between each terminal. I expect they will be very low resistances.

If you have a 24V screen and run it from 12V then it will just run cooler (approx half the temperature when running at 24V).

I will check with one of the maufacturers we use to see what resistances to expect and get back to you (we fit them to boats).

It won't be 1/2 the wattage it will be 1/4 the wattage. It will draw 1/2 the current, P=I2R (wattage = current squared times resistance) so for the same resistance and half the current you get 1/4 the wattage.
 

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Unimog S 404.114
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there should be 3 wires, Colors Brown ground,
black / White one side life
and red / White other side life.
if wrong affiliated-> short circuit.
Fuse enough amperes?

If widshield is a 24V Version verry low heating on 12V, but no electrical probs.
 
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