VANS ISSPO 40 Amp Guage diagram

[daberges]

Has anyone got a copy of the INTERNAL wiring diagram of the 40 AMP ISSPO gauge.

Heres the history. I have the shunt fitted between the battery and the master relay. This was an add in gauge as I already have a Volt meter and a low volt warning along with an alternator fail warning. Thus I put the shunt before the Master Relay and not after.

Heres the problem. The VANS gauge has 4 connections behind it. 2 inputs from the shunt - 1 X instrument power and 1 X Ground. (Plus a lamp - but these are seperate) Somehow I am getting a battery drain when the master is switched off. It appears to go via the shunt to the ground through the instrument ground. (Bypassing the M/S)

Does anyone have an internal for the gauge so I can confirm my troubleshooting? Does anyone have better ideas? Is my gauge working?

My thoughts are

Move the shunt after the solenoid.
Get a gauge that does not require instrument power and ground.

Regards Duncan

[lucky333]

The shunt should go between the output side of the master relay and your main bus (not including the starter). You are probably seeing the unswitched battery current through the input resistors of the shunt amplifier inside the guage. Plus the guage circuitry itself consumes some power.

Also, its not good if the inputs have voltage but the power is off the (+) power lead. Depending on the input circuit, that could cause heavier drains or even let the smoke out.

I don't have skiz of the ammeter internals but have traced out the fuel guage and can send if you want. (If I can find it). Its a 270 deg meter driver with an amplifier to scale the fuel sensor to swing the needle. I would assume the ammeter would be similar with a different front end (a simple difference amp to drive the meter chip)

BTW There have been several lively discussions on the forum regarding shunt placement and how it affects what gets measured.. Might want to search for some of those as well.

Have fun.
John.