riddle me this...

According to my VIN plate my CJ is a 74. The VIN tag (matching numbers) on the dash says manufactured in November of 73. This tells me it was made in 73 for the 74 model year. I have the Haynes manual and need to use the 72-73 wiring diagram since I have a points ignition and external voltage regulator (motorola.) The Haynes 74-75 wiring diagram shows an internally regulated Delco alternator. Why would a 74 have the 73 wiring system? :? Were they just using old stock? Part 2 of the riddle... My speedo matches the 73 diagram style with an oil & amp light in the cluster. But my dash has cut outs for an oil & volt guage that matches the 74-75 diagram. Why not just use a 73 dash? Did they just run the wires to the guages instead of the speedo? It doesn't really matter, but curiosity killed the cat and satisfaction brought it back. My money is on Timgr the jeepin nerd for the answer. Thanks

 

My assessment - the Haynes manual is wrong. Get a 1974 FSM and compare. Haynes made mistakes when they condensed manuals for multiple years into a single manual.

Oil and amp/voltage gauges were available from the regular option list starting in 1972. Any of these Jeeps could have had gauges, or not, depending on the build sheet.

 

I like Tim's answer.

I would add that Jeep was known for some model year carryover of parts etc.

 

Also, the central improvement of the '75 wiring harness is the separate fuse box, under the dash. This is a big improvement over the earlier inline fuses scattered in various places in the wiring harness. AFAIK no '74s got that harness, so a '75 diagram is simply wrong for a '74. It's possible that '74s may have gotten the new-style harness in '74 as a mid-year change or in late '74 as the '74 parts were used up at the end of the run (seems unlikely, considering Jeep has to keep some of the old harnesses for parts stock), but certainly that would not appear in the '74 FSM.

It's possible that Haynes referred to the Holland interchange manuals that junkyards use to determine year-range for used replacement parts. In that case, it would be the Holland manuals that are in error, and Haynes is just repeating that error.

It seems to be common knowledge that the Haynes and Chilton's manuals contain a lot of mistakes. I presume they can be helpful if you keep their high error rate in mind. I'd advise you shelve the Haynes manual and buy a copy of the factory manual for your Jeep's year. They are available as reprints, and original copies come up on eBay frequently.

 

Hey Tim,

Is a factory service manual the same as a technical service manual? I need to buy one for my 73 and I want to make sure I purchase the right book.

JM

 

Yep. Different name for the same book. TSM is Jeep's name for their FSM. "FSM" is a generic term.

 

Tim is right. My 74 originally had an externally regulated Motorola alternator and a Delco points ignition. Haynes is not a definitive source, just a compilation of diagrams from FSM's.

 

Thanks Timgr. I bought the Haynes book prior to finding this forum. Following your advice, i've downloaded the 74 FSM, but unfortunately my printer didn't work with Vista. That problem has been corrected. I don't know why or how you know so much about jeeps, but your answers have been very helpful. Thanks again, now i can stop the wonderin and get to workin.

 

It is likely they had left over parts from the 73 model year. Happened all the time back then. I had a 1980 Toyota Supra and the wiring and most parts had to be ordered from a 1979. Very common.

 

do mind sharing what the last 5 of your vin is? I am trying to narrow mine down so i can get a replacement vin decal

 

30941 the engine block code matches up with the manufacture date on the vin sticker. I have a 258 I6. 1st 3 digits are 611 which decodes as 1973 november.

 

I know all that, but that doesnt tell you the DOM.

 

Thank you very much, with that I am able to confirm that mine is a Nov 73 as well DOM. Mines falls between yours and another guys with a Nov 73 DOM. I am # 34306, was originally a renegade w/ tailgate delete. still have the original mag wheels, and color was the Plum Purple color. Thanks again.