The Stovebolt Site Forums The Shop Area The Electrical Bay Incorrect Wiring Diagram for my '48?

I recently pulled the gauge clusters and repaired the fuel and temp gauge. Not wanting to trust my memory in re-installing the gauges, I went to my trusty 1948 shop manual to be certain the connections were right. Nothing made sense! For two days I have scratched(and bumped)my head under the dash trying to get things right. Long story short, my truck is wired for a 1947. Thank goodness I looked at alternate diagrams before I went nutcase or did damage . My father bought this truck new in 1948 and the truck became mine in 1966. I am the ONLY person who has has their hands on the wiring in all of these years so I know this is how it came from the factory. Is it common for wiring swaps at the factory, as in wiring a '48 year with '47 schematic? I'm SO curious, thanks for any replies!! The truck was built at the Van Nuys CA factory.

It could be a 1947 truck sold in 1948?

What is the engine serial number?

What are the head and date casting codes?

http://www.1954advance-design.com/Web%20images/casting-code-photos/low-press-codes-ser-nums.html

Thank you tclederman for you reply. Adjacent to the left of the distributor the boss is stamped FBA208845. Below that, a circled '48' is present as well as numbers I cannot read tonight without getting under the truck which I will gladly do tomorrow since I have just had a shower and cleaned myself of this day's grease - bruises didn't wash off unfortunately. I'll get back at you with those other numbers tomorrow. Thanks!!

FBA = 1948 3100 truck engine

The other codes will confirm the year of the engine (it could be a 1948 engine, or it could be a replacement engine that had an engine code changed to match your truck (for registration).

Just to chime in my son's 1946 2 ton was sold and titled as a 1947. This site is how I found out the correct year. This is a great place. Jeffrey

Hello tclederman, the engine has the number 3835258, it is the engine that came new with the truck. The sales receipt has the date of May 24th, 1948. I wasn't very clear in my initial inquiry and didn't mention that the 1947 and 1948 wiring diagrams are identical except for the ammeter wiring. The wires would not allow me to wire it the way the 1948 schematic showed but everything was perfect for the 1947 schematic. Here are the differences : http://s23.photobucket.com/user/littlebuddytoo/media/48Chevy/Ammeter.jpg.html
So this ammeter configuration may simply remain a mystery! Thanks for your help!

Is there a chance that the engine casting code is 3835253 (used in 48-49)?

Post the head & block date casting codes, if you are interested in knowing when the head/block were cast.

Quite possibly tclederman, what I see as an 8 might be a 3. I'll scrape around and look closer. It's really hard to poke my head in there to read it well. As for the head, I took it to the local auto parts store for a rebuild in 1967 and they returned a head from a 235 to me. I was SO MAD but my original core was gone, gone, gone by then and a teenager had zero clout in a machine shop in those days. They basically told me 'tough luck kid', we have your money now go away.
Thank you for your knowledge and help!

The big story here is who would have guessed there was any difference in wiring a 47/48? It's so very basic, what's the difference that made you crazy?

Hi bartomos, thanks for jumping in. To those who are familiar with auto electrical, there may be no difference between the '47 and '48 ammeter wiring http://s23.photobucket.com/user/littlebuddytoo/media/48Chevy/Ammeter.jpg.html but to me, the two diagrams of the ammeter wiring are the difference between baking a cake and barbequing short ribs. Are the two diagrams in actuality the same via different routing? That's why I come here for your knowledge and appreciate everyone's input. Thanks buddy!

I actually did not know. I don't have AD trucks. I was really wanting to know what you noticed. You said you were doing gauges and nothing made sense. That made be wonder. Not meant to belittle you littlebuddie.
I see by your link what you mean. Why you were confused. I don't think it makes any difference which side of the ammeter a load is on. It seems back then they probably wired it that way (47 vs 48) because of where, physically, the wires were coming into ammeter, routing as you say. Or the ammeters where designed differently. You see they had the voltage regulator on opposite sides.

Just be careful, back then they didn't appreciate the value of fuses much either. Make sure you add fuses to everything. Not that you don't know more about it than me.

Ref info: Autometer shows ammeter wired as follows: one terminal from batt, other terminal to everything else but starter motor. "If it does not read properly, switch wiring."

tclederman, thank you for putting up with me and for your patience. I am a 63 y/o woman doing the best I can so I am much obliged for your assistance. The engine number is indeed 3835253 with the number 21 below that number. But this is sort of a moot point on my part since all is working well, I was just curious about my particular situation so thanks for your help and I will call this thread 'solved'. Many thanks Sir.

Thanks for your input bartamos. Since I am not a wiring wizard, I take what I see in the schematics literally without understanding certain basic automobile wiring variations. Anyway, everything is working fine. I am happy to report that I was able to fix both the fuel gauge by re-soldering the coil wires (micro surgery) and the temp gauge by slightly bending the Burdon Tube. That alone probably saved me $150.00 in after-market repro's. These two gauges had not worked for over 20 years so I am able to get rid of the under dash mount Stewart Warner auxiliary gauges which were nice but didn't 'fit' the authenticity of the truck. Thanks everyone!

Excellent job. That is the bottom line, everything is working. You did it by perseverance and logic, two great attributes.

Good work, good patience, and good thinking, littlebuddie

Thank you my friends, without you all here to advise a lot of us would be in a real pickle!