I have a 1988 Dodge Shadow ES where the alternator won't charge if it has been raining for several days i.e. very damp weather. If I drive for a little while and the roads aren't wet then stop somewhere for about twenty minutes and start it, it starts charging most times. I had the alternator replaced twice.
Any suggestion on how to troubleshoot this?
Thanks, Em
I would be checking the belt.
Fan belts can 'look' perfect and be tightened properly but be polished up so they don't grab the alternator pulley well enough.
I test them with a cold off engine and see if I can spin the alternator pulley by hand.
If I can spin it by hand, there is no way the belt will grab it when the alternator is under load. It takes a few HP to spin up an alternator.
This gives a no charge when first started or no charge when humid or wet until it all heats up and dries out. Even then, it won't be fully charging up the battery, there still will be some slip.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT'sEmmet Cumm>
Ed and Mike, thanks for your replies. The belt has been replaced since I first had the problem and it appears to be tight.
I would try using "Wire Dry", spray it on all electrical wires (including the plug wires) and spray the inside of the distributor cap (or whatever essentially replaces it on a distributor-less system).
Just offering an alternative to the slipping belt solution.
Another idea is to take the alternator to a shop and have them test it, that will tell you for sure if it's bad or not.
Another possible problem is the battery. You might think it's good, but you should remove it from the car/system and "load test" it. I find that if you leave it connected to the car, readings can be misleading.
-PapaRick
-----------------------------------------------------------------------
Emmet Cumm> Ed and Mike, thanks for your replies. The belt has been replaced since I
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.