technical cooling system question

[arkus]

on my '63 the gauge pegs past 240 after a very (3 minutes ) short run time. engine is not hot and steaming/thumping. per workshop manual this can be checked to pinpoint either faulty sender or gauge. i have a restored spare gauge to do that with AND here is the question. there are two electrical connections, one at the very top on the back and one 1 inch lower. my schematic shows  wire 55B to one post and wire 14 to the other, but is not specific to which post gets, say, wire 14. really don't want to take a chance and ruin the gauge. can any of you really technical guys help? thank you.

[Ntenna]

Pegged gauge usually means shorted circuit on sender side or shorted sender. You can check by just taking sender connection loose, float in mid-air and turn on ignition w/o starting. Gauge should just sit there at zero. Tap sender wire to block, have someone watch and gauge should peg. Can verify connections tomorrow on our 63 though, if someone doesn’t get to it earlier.

Engine really can’t reach 240 in 3 minutes run time. Has to be something shorting after 3 minutes, IMHO.

 

 

[adamderosa]

On the diagram  I have it shows wire #14 (orange) on the top,  wire 47D (white) should be on left if looking at the gauge from the back, or towards the center of the car, and wire 55B (Grey with Black trace)should be at the bottom. 

Avanti Temp Gauge Wiring.pdf

[arkus]

that's the same diagram i have. the way it is presented with the description "heat gage" horizontally printed across the picture makes it appear that the mounting posts are top and bottom, giving you the locations for 55B and 14. this is not the case as the mounting posts are right and left and because you could ground either mounting post, the location of 55B and 14 could be reversed. in short, the diagram lacks that direction. i'm inclined to think that 14, the wire from the sending unit, belongs on the bottom electrical post.

[Ntenna]

Looking from the bottom the gray wire with black stripe (power from fuse box and ignition switch) is on the bottom terminal. The orange wire to the sender (barely visible) is on the top terminal. The white push-on plugs on the temp gauge studs are for grounds for windshield washer and clock.

[arkus]

thanks for "going the extra mile". helps a lot!