electrical gurus, need info

is there any difference in the ohms required to operate the fuel gauge for the under seat tank V/s the rear mount tank? or a better way to word it is the gauge the same for both? my insturment cluster came out of a rear tank model, and i will be using the under seat tank, i know that the sending unit is different due to bigger tank, and tank shape, just not sure if they use the same gauge

 

You should measure the ohms of the sending units, than you know if the gauges are different.......

 

ok, i see, well i am going to order new, and dont have either, the rear tank unit was bad, and my orignal under tank was 24 volt , military, bad also

 

i am seeing this alot here latley, if a fsm is my magic solution, then why bother even having a site like ecj5:? thought this place was about helping each other out

 

the FSMs for 71 and prior don't always have the info....like what the original poster is asking for. and yes, I looked.
the FSM merely states to try a new sender out of the box (well grounded) to eliminate the tank sender.
If I recall, I found the info on a cheat sheet that came with a dial tester for testing fuel/temp gauges..you dialed the resistance value and observed the gauge needles.

that being said, I don't have the info being asked for....

but a search, pulled up this info:
http://www.earlycj5.com/forums/showthread.php?t=62777&highlight=fuel+sender+resistance+values

 

As an educated guess, I think the later lock-ring type under-seat tank will be the same ohms range sender as the under-floor tank senders - at least through 1980.

The values for the '77 manual are given in the above linked thread. My '75 manual gives the same values, so I presume that all the earlier under-floor tank senders have the same values. This would also indicate that the late under-seat tank senders have the same values, since (I assume) they use the same gauge in the same cluster.

I recall that the under-seat tank sending unit with a lock ring is NLA, so the question may be moot if you have that tank and no sender. You could install the rear-tank sender if you modify the pickup tube and float arm to fit the under-seat tank. Then you would be guaranteed of having the same ohms-range for both tanks.

 

I have used several gauges on both underseat and rear mounted tanks. They all seem to work fine. I did have a problem with the temp gauge on my dauntless though. I ended up soldering in a 10 ohm resistor and now it sits right in the middle.

 

when the FSM confuses me.
i come a runnin here.
one way or another i have ALWAYS gotten the answer.:tea: