Voltage regulator removal disrupts fuel and water gauge signal after alternator swap?

[charbly]

The title says it all! I recently put in a Saturn internally regulated alternator off a 2002 Saturn sl into my 1975 620. I followed the directions in the many different alternator swap articles on this website and have had mostly success with the swap.  Made a jumper pigtail out of the voltage regulator that was removed, bypassed the choke heater relay, but what I realized after jumping in my truck and starting it up, is that the temp and water gauges are not activated. I did check to make sure they work by grounding the water wire to the thermostat and the gauge climbs and works. It looks like the voltage regulator sent an 8 volt signal to these units, and I’m wondering if my alternator since it is for a separate application doesn’t have this attribute to monitor voltage to specific gauges. Can I make a voltage relay that sends 8 volts to the yellow wire which is common in both gauges so they get the correct feed? Any solutions or people with the same problem?  Thanks!

[banzai510(hainz)]

How will you get the 8 volts to the gauges?

unless you make a voltage divider to get 8volts to feed both gauges.really it’s in the gauge cluster behind where the gauge volt reg is.need to see if it’s getting the 12 volts In. And say the 8 volts outthere I guess but hard to measure when installed. Looks like a little metal can behind instrument panel

 

you close the fuse by chance? Really I’m guessing on this one 

 

gas gauge work just by turning key to On?

[charbly]

WHOOPS! Solved!!!! I had my seats out after replacing the seatbelts while simultaneously doing the alt swap and I had forgotten I had unplugged the cabin connector under the seats ( where the gas gauge white connects)   Plugged back in and I have power again! Oh boy, it’s nice to know it’s an easy fix but hard to swallow how thick my skull is. Thanks for responding hainz, somehow your post jogged my memory of the wire going back to the tank and bingo! Solved. Whoops!