Rally dash gauge voltage. 5v or 6v nominal?
"Rig it up" and test it.
1...There are known resistor "standards" for the 3 main gauges "points" L, 1/2, H These test resistances are "supposed" to be the same for all gauges
2...The fact that your senders may not provide those resistances does not change the fact that you need some place to start
3....There is a device you can buy for ?about 50 bucks called a "meter match." This is useful for correcting such as fuel gauge readings, but could be used on temp as well.
The OTHER thing you want to do is to make sure that harness drop or other problems is NOT causing overly high system voltage---aka overcharge
"Rig it up" and test it.
1...There are known resistor "standards" for the 3 main gauges "points" L, 1/2, H These test resistances are "supposed" to be the same for all gauges
2...The fact that your senders may not provide those resistances does not change the fact that you need some place to start
3....There is a device you can buy for ?about 50 bucks called a "meter match." This is useful for correcting such as fuel gauge readings, but could be used on temp as well.
The OTHER thing you want to do is to make sure that harness drop or other problems is NOT causing overly high system voltage---aka overcharge