Updated***

Hi all,

my alternator/generator on my 1999 Discovery Series I is in the process of kicking the bucket so I bought a used Denso from Rockauto. Came today and I go to install only to find the alternator I’m pulling has three terminals while the new Denso only has two terminals: B+ and D+.

Did a little digging and it looks like:
B+ Terminal is for battery positive
D+ Terminal is for ignition light (battery power light)
W terminal (spade connection) is for speedometer

So, what I’m trying to figure out is if I can put the Discovery’s D+ and W together on the same nut (speedometer and ignition light) while avoiding any ill-effects? Both wires are of similar gauge and when looking at the construction on the old alternator the D+ and W bolts to which these connections are mounted with ring terminals are only half-an-inch apart from one another and appear to be connected to the same material at their base.

Any insight would be appreciated,
Thanks!

 

A used alternator with one less terminal. This won’t end well.

 

Conclusion: I ended up using a multimeter on my old 3 terminal alternator to check for continuity between the D+ and W terminals. There was continuity between the two terminals which made me confident that it was fine to double up on the new Denso alternator with only two terminals, however it was at that moment I realized the mounting bracket for the Denso was opposite that of the mounting bracket on the truck so I wasn’t able to install. I ended up getting an 100 amp 3-terminal amp instead.