Centigrade to Fahrenheit Conversion
 

I just pulled two instrument clusters from mid 80s 126 models. From all I can tell these are US version cars, definitely not grey market. Both of the outside temperature displays (the one at the bottom center of the cluster) read in Centigrade. My uncle had an '84 300SD and his temperature display read in Fahrenheit. Is there some programming trick, such as temporarily grounding one of the pins or turning the lights on multiple times, which will change the temperture display so that it will read in Fahrenheit?

my 84 is C*
 

my car was bought from a dealer new in Dallas and the outside temp reads in C* not F* - I'd be curious to see if there is a way to change it

There is no way to change it. Either the gauge comes in °F. readout or it comes in °C. readout. A gauge of the opposite type can be obtained for $40-$60 typically.

Double it.
Subtract ten per cent.
Add 32.
Save your money.

Exactly.


Or:
0C = 32F.
5C = 41F
10C = 50F
15C = 59F
20C = 68F
25C = 77F
30C = 86F


Cut and print and put on dashboard.:D

Or... carry a laptop. I have become familiar with this website ever since dropping my kid's electric thermometer and now it only reads in Centigrade, which is not helpful when talking to a doctor on the phone.

http://www.metric-conversions.org/temperature/celsius-fahrenheit.htm

Thanks for your responses.

I had occasion long ago to memorize the 10 degree increments on the Centigrade scale so mental conversion is not a problem. You left my favorite conversion out of the list:

16 deg C = 61 deg F

I had just noticed a spot on the circuit board where one or two parts were missing and wondered if adding the appropriate parts would effect the conversion.

You might be right about the unit in my uncle's '84. He was not the original owner. I know the unit was not replaced on his watch.

Conversion just adds confusion.....
 

Folks,

Consider just learning and working within the Metric System......there is no meed to convert, other than your personal peace of mind......

0*C...........Cold
20*C.........Warm
40*C.........Hot

As you get used to looking at the Metric values, and thinking what they should be in Metric......rather than converting.......example......Oil Pressure, if you see 3 Bar you know that you have plenty and do not need to do any mental recalculations to reach the conclusion that 3 Bar is approximately 45 psi and therefore Good, and if you see 1 Bar you know that it is on the low side of Good and not approximately 15 psi.....

Most of the other parts of this earth use the Metric System, get with the program.....I don't care if you like it, the reality is that China is using the Metric System, and they are now manufacturing most of the stuff in WallMart, so your need for Metric Tools will increase as well......

SB

Ok, how about this. The one point that the Centigrade and Farenheight temperature scales match is –40°.

Zill.

This little convrsion is worth the price of my annual subscription to Mercedesshop.com. Oh, wait, there is no subscription fee. OK, its worth MORE than the annual subscription fee!

Thanks.

I gave up trying to do the 5/9 conversion in my head. This one is easy!

That conversion might get it close, but it is not exactly correct.

To be correct you multiply times 1.8 and then add 32.

Doubling, then reducing that figure by 10%, is just a mental shortcut for multiplying by 1.8.

exactly the same results. exactly! check your algebra.
John

Yes, that is correct. I peruse things quickly and missed the reduce by 10%. It doesn't sound like a shortcut to me, however, it sounds like a "long cut."

It seems simpler to just multiply by 1.8, but being an old electronics guy that is accustomed to throwing numbers around in my head, maybe that shortcut doesn't work for me, where it would indeed work for someone else.

25 times two is 50, less 10% is 45.

or

25 times 1.8 is:

Well, let's see. 25 times 8 is 200. (Remember that figure) 10 times 25 is 250. 250 plus 200 is 450. Now, where's that decimal go?