77 blazer temp sender location

[jserrato714]

Hey forum , just came up on a 77 blazer with a newer sbc350. My temp needle is dead so i cleaned the terminals on the gauge and nada.. so then i checked under the hood and realized there was no temp sender on the driverside head above the headers..i found a female spade connector on a dark green wire coming from the firewall junction block...well i was told by the previous owner that the engine is a newer motor pre 88 since there are no vortec style valve covers. It has a smaller square head plug where the sender goes on all chevys..looks way smaller than the 1/2 thread sender which i bought for the og motor.. i read on this forum to use plumbing reducer to make it work..is that a good idea? I mounted my sender on my thermostat housing hooked up the green wire and my gauge is still dead. Does the green wire need 12 v or is it a ground wire? I know that u will get a more acurate reading at the head but the thermostat housing will have to do for now... Is there a fuse im missing for that green wire? Feel free to chime in..thanks
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[jserrato714]

Any ideas....i ran a new wire from under the dash from the temp gauge to the sender and nada. I went a head and added some after market gauges from harbor freight and some how it does not read my temp either. Im thinking i pinched the line on installation or u get what u pay for.
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