Battery light on- lost tach at same time?

[nopower65]

I'm ready to shoot this truck. While towing boat home- first lost the turbo boost (on a 6.5 that the GM dealer says nothing is wrong with!! Can't wait for the turbomaster to get here) then the battery light comes on and the tach quits.

Local parts store says the batteries are ok. They claim the alternator failed. Before I spend the cash for an alternator, I'd like to be sure. Why would the tach fail at the same time? All the other gauges work fine?

TIA

-jim with a 6.5 and no power.

[rjschoolcraft]

The tach reads the alternator for its input.

The alternator is dead.

[Turbo Al]

Ronnie Joe is correct the tack is hooked up to the altenator. On my 1993 the tach can die (no battery light lit on dash) and the altenator will still funtion normally.

[Budd]

I had the sasme thing happen to me on the way home from work one, except I was only able to accelerate upto thirty mph. It' still under warranty so I took it the dealer i bought it from. They wouldn't even look at the alternator untill i bought new batteries as they were shot. Had the truck only three weeks when this happened so I complained to sales manager that they should spring for batteries and they did. After they got the new batteries they tested the alternator and low and behold it was dead. This was after about a week arguing with them that it was indeed my alt. and not batteries. Ended up costing $50 for the alt. instead of $200 for new batteries and alt.

[nopower65]

Thanks for the help. Put the new alternator in, fixed like a champ!

Appreciate the help from everyone.

[nopower65]

Thanks for the help. Put the new alternator in, fixed like a champ!

Appreciate the help from everyone.