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Pabloairmale

2000 quest alt on a 71 521 upgrade

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Started the alt upgrade! got a used alt form a 2000 quest (125amp) $40 at scrape yard. had to cut and grind but all mounted nice. 

iam at the wiring stage and not sure what to plug where.  it looks like the old alt has a internal reg (hitachi l35a). the new alt has a parrallel plug, one is yellow and black and the other is blue with white dots. does anyone know which goes where? thanks

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You are aware that you must modify the wiring to, and remove the external regulator to use an internal regulated alternator, correct? What I have done is remove the external regulator and trim the wires off leaving the plastic plug with long leads. Join the White and the Yellow wires. Join the White/Red stripe and the White/Black stripe wires. Be sure to solder the two connections and use heat shrink tubing or electrical tape. Remove the unused wires. Now simply plug this modified plug back into the engine wire harness. Nice and neat. Your '71 should have a manual choke so there is no need to modify anything else.

 

The two wires on the T plastic plug on the 521 harness to the old alternator must join to the Quest plug. I've done this and got it wrong. It works though, and had it this way for a couple of years before I found out. No harm done. If wired incorrectly the RED charge light doesn't come on with the ignition. Just switch the wires. You have a 50% chance of getting it right.

 

Last is the output wire from the Quest alternator. Get some 10 gauge wire and must be able to handle the output. Crimp large lugs onto the ends and connect it to the starter lug for a good solid return to the battery positive terminal. Use some split plastic harness covering to insulate it from any chafing.

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Is the external regulator still hooked up? It's a 6 wire plug located on the passenger side middle of the engine bay.

 

This is for a 510 but basically the same for 521:

 

wiring_diagramIR.jpg

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It looks like or it is a inter volt reg alternator.

We dont know post photos. Is the External volt reg still on there?  If yes I highly dought its a IR alternator.

 

 

PS is it going to fit in there?  Most L 16 the bolt holes are different size for the ears and block mounting. Smaller bolts. Im sure the Quest is the bigger bolts.  Plus the bigger Alt mayb hit the steering mech or fan belt

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I'll get you a pic of mine in a bit. Post a pic of your quest plug/pigtail if you got that

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On the new pigtail, the right terminal, as looked at straight on with the clip up, is your sense wire and hooks up to the top of the "T" terminal on your 521, which should be the yellow wire.

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Yes. Blue wire then hooks up to the leg of the "T" connector, which should be white with black stripe on your stock plug

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