Do you think an 80 amp alternator could replace a 100 amp.? The 1992 940 with the 100 amp alt has a few things that don't work such as...

The ac
Radio
Heated seats
Power sunroof
Power antenna

 

I doubt swapping alternators would fix those problems, unless they are due to your battery discharging and not recharging.

 

What i meant but wasn't clear on was will a lower amp alt be ok to replace a higher amp alt considering all the electric stuff that doesnt work on the car with the higher amp alt

 

well, if it fits, it should work adequately. most of what you listed uses very little power (except the heated seats), I'd keep an eye on yoru charging voltage (thats the voltage across the battery when the car is running), ideally it should stay around 14V

 

What is the battery voltage when the engine is running.

 

The 100 amp alt is on my 1992 940 and it ain't running right now. The 80 amp alt is on a 1989 740 parts car. Both cars have b230 na engines, but 1 is regina and 1 is bosch.

The only thing electrical on the 940 that works that the 740 did not have is power mirrors.

Based upon my kids story of what happened while driving the 940 I think the alternator died.

Im gonna test the alt and go from there.

 

charge the battery and the car should run even without an alternator, at least for a few hours or so (headlights and all power hungry accessories off).

first level test for a bad alternator is measuring the voltage at the battery when the engine is running. 80% of the time, if the car is not charging (voltage not going at least 1V above the battery charge voltage, alternator voltage should be in the 13.6-14.2V range), you need a new regulator/brush assembly. 10% of the time, its a ground wire. remaining 10%, its actually a bad alternator.

 

I put a fully charged battery in and the car started. It did stumble a bit at first. Then smoothed out and ran fine.

Drove the car to the lps where the battery and alternator tested fine.

Topped off the gas tank with just 6 gallons. The car has seemed to have some issues when under half a tank. Its a 940 regina with just one in tank pump.

I've noticed the dash gauge for the fuel level is sometimes slow to work. And the dash gauge for the temperature bounces around quite a bit.

I don't know...my kid is out with it now...see what he says when he gets home.

 

It was an issue with the alternator belt.