I have a 92 Truck, The charge and brake light were coming on weakly and intermittently so I changed out the alternator with one I had laying around that was good when I pulled it. Now, when I hit higher RPMs the lights come on strong and I get a voltage spike, as in the heater fan sounds like it's on steroids. Any ideas? It doesn't seem like I could have 2 bad alts but stranger things have happened.
Thanks