My car sat for 3 months and then I tried to start it. When I turn the ignition on, everything looks fine until I hit the brake pedal and the dash lights dim. If I don’t press the brake, the dash light dim when I tun the ignition to crank. Either way the starter either clicks or doesn’t do anything and I hear a humming sound. My husband said, “The battery has been charged and measures 12.62 volts,” but the cigarette light voltage measures 12.26, so they are not the same. I have tried jumping it and I still get clicks. Is there anyway for me to troubleshoot this or I do I just need to go to an auto electric shop?
I wouldn’t worry about the voltage difference between the battery and cigarette lighter as that’s probably due to a normal voltage drop through various wire connectors, etc.
The battery voltage is about 12.6 but what is the voltage when you turn the key and energize the starter motor? If it takes a sharp nosedive down into the single digits then the battery is either run down or bad or the starter motor is failing.
Offhand,it sounds like the battery is run down and that’s to be expected after sitting for 3 months. Sitting idle is not good for a battery because they tend to sulfate and that’s a battery killer.
Time to check and clean connections on the battery, battery ground, and pos lead on starter motor. A loose or corroded connection sounds like the problem to me.
It turns out it was the starter. I took the starter apart and replaced the copper contacts. If you google search denso starter repair kit, you can find a bunch of places that sell them.
Good you figured it out, and figured out the cheap repair. I was about to mention the solenoid contacts. Did you also replace the round disk along with the side contacts? When mine went bad, I just replaced the side contacts and had to repair it again in just a few years.