I picked up my car (69' 350hp) Friday from an "experienced/reputable" installer of the "Vintage Air" air conditioning system. The shop installed a Gen II system along with an electric cooling fan. On the drive from the shop back to work (20 miles) I noticed the ammeter reading about +20 (before AC it read just above 0). On trip home from work, car stops running - electrical failure. Turns out the fusable link to starter fried. Replaced fusable link and car runs fine except now ammeter reads +35 to +40 all the time, even with AC off. The alternator on car is about 7 months old. Its a 63 amp rebuilt Delco-Remy. Battery is new also. The installer changed the pulley on the alternator to a duel pulley although only 1 belt is used.

Now the questions.

1. Will the electric fan and electric operated Gen II system increase the current draw on the alternator that much?

2. Will replacing the alternator with one rated at a higher amperage help and if so, any recommendations for heavy duty alternators?

3. Do I have other problems?



[Modified by rickc, 8:51 AM 5/12/2002]

 

I don't have much time to reply right now, but I'd say your installer connected the AC/fan system to the wrong spot in you electrical system. It was/is tied to the battery side of you ammeter "sense" wire and should be tied to the alternator side. I need to look at my wiring diagrams, and if you could get more info on you AC installtion, if they're still talking to you. And I'd guess it's working now because they replaced the fuse link with a large wire that can take the current, but not protect the car's wiring. Not a good idea.

You can get my email from my forum stats if you want to pursue the issue. That large of a ammeter readings is NOT normal.

Andy

 

The 63 amp alternator should be more then enough, I run a stock 61 amp and the factory air and dual flex a lite fans every thing worked fine. I did remove the fans but that was for other reasons. Buttom line the main power feeds to your A/C and your fan should feed from the + side of your Batt or at the Starter + side that is the same hook-up as your + Batt. I do not bother with the amp meter to confusing I just make sure that my voltage output is more then 14 volts with all the Lights, A/C, and other power options on the vette. " When doing this test make sure the vette RPMs are at least 1500 rpm or higher and of course make sure you have a good fresh Batt.

 

I have to disagree with the previous post, for two reasons. First Chevy didn't tie the AC fan in at the starter, and second if you do tie to the starter, you loose the protection of the fuse link that was burnt out. These circuits are not made to handle the load presented by an AC load, along with an electric cooling fan, then the normal load of the car on top of that. The 35 to 40 amps you're now seeing is in all probability the current going to the cooling fan from the alternator down to the starter and through the "fuse link". A fuse link that I suspect was replaced with a large gauge wire (or not replaced at all). The AC load is probably coming from the horn relay that ties directly to the alternator. This current will not "show up" on the ammeter because of the way the ammeter is connected. This is where Chevy connected its AC fan, but it also used a 30 amp fuse in the line going over to the fan motor.

I'm not sure where I'd put a heavy load like a fan. On the starter overloads the fuse link, on the horn relay/alternator you may take out the fuse link if the fan comes on but the motor isn't running. All the current is then coming from the battery, thru the fuse link, and then to the fan.

If you haven't received some guarantees from the "expert installer" I'd get the fan out of there before you loose the whole car to an electrical fire. (My opinion as an owner of a '69, 30+ years of mechanic experience, and a degree in electrical engineering.) All this can be made to work, but it'll take time, planning and knowledge. And from your experieces so far I wouldn't say your installer has the necessary skills or knowledge.

Just my opinion.

Andy