'00 1-ton 4wd speedo and tach

[crabtruck]

So no t-case sw, or TCCM as on lighter trucks,
but still actuator and on a 3500 t-case sw if a diesel,
and as mentioned the aux batt relay.
However, if this is a diesel, the second battery is hardwired, not relayed in.
Also supplies one spare "jackk" in the conv cntr.

[Wyley87]

well it not a diesel, its got the 454 Vortec

[Wyley87]

***********UPDATE**************

ok went to my dads today to check out his truck someone left the d-ang lights on so any codes that where there are long gone. I unplugged the FWD acutator(i didn't think it had one of those cuz the 4wd is on the floor and not push button). Still blew fuses untill i put a 30A in and but its a 20A socket. so i took it out and remembered about the aux bat you mentioned so i unhooked it and low and behold no more blown fuses. So i guess a narrowed it down as far as that goes? Also the guy at autozone told me that i could take the speed censor home and it it didn't fix it I could just return it for something else no big deal.


So what do i do now?

[crabtruck]

duh ! buy the guy a beer.

When batt is charged again you may no lomger have the problem
if it was just lock on a glitch. If not codes may be available.
And since you have a free to try VSS...try it.

[Wyley87]

well some i failed to mention is that we unhooked the aux battery and the regular battery and put it on a charger of mine. what would cause the aux bat to blow that fuse?

[crabtruck]

Not clear what you unhooked to stop fuse blow, relay or batt ?
May be bad relay, ohm its coil and look for local cause.

[Wyley87]

ok its not the speed sensor still no tach or speedo

[crabtruck]

2000 Chevy 1-ton 454 Vortec 4wd old body style. (just refreshing my memory )

4wd fuse blows at facto 20A but not at 30A ?
See if that's still true when Aux Relay for Aux Batt is out.
If 20A still blows, check for accesories added to conv center.
Believe it is a Brw wire supplying "Spare Power Source" (F3 ?)

In fact your speedo problem may be related, since the wire from
ECM to speedo also passes through Conv Cntr.
I don't have enough info on that cluster to say if a hard short to hot
may have harmed speedo.
Odd too, since the tach is a seperate feed direct from ign coil. (Wht)

Logic would also indicate that this is not a VSS circuit problem if shift points
and engine performance are good. VSS is good to ECM.
Therefore ECM to gauge is problem. IE: wire or gauge.
Look for shorting of that wire with an extra look when in the neighborhood
of the 4wd circuit. May need to pull cluster and look for smoke.

[Wyley87]

well i do know they both went out at the same time. also with the aux battery unhooked the 4wd fuse dose not blow.(the main battery is still connected)

[crabtruck]

Disconnected the batt, not the batt relay ? ?
Still not clear whether this a relay prob or not.

Like I said, inspect conv cntr for overload and for crossed/shorted wires.