curtie94

Hi I have been having electrical problems in my 91' Honda Accord. At idle all the lights are dim and the heater blower is slow. But when the gas is applied all the lights and heater get faster. So today I went and checked for voltage drop from the battery. The wire that goes from the battery to the fuse block had -60 milivolts and the the starter wire had -2 millivolts.

SO i'm pretty sure I need a new wire to the fuse block. Is that right.

GhostAccord

Sounds like you have ether a week battery or dead alternator to me.

Not sure how you are getting 0.06v from the battery and the car is still actually starting and running.

curtie94

I was checking voltage drop from one side of the wire to the other.

GhostAccord

So are you getting a 0.06v drop over the length of the wire going from the battery to the fuse box? If you have 11v-14v from the battery and a drop of 0.06v then I would say your OK on that wire.

curtie94

Ok and it was .02 volts to the starter. What I notice is that when the car is revving at about 2000 rpms I get 14 volts but at idle 750rpms I barely get 11 and the alternator puts out 10.5V is there a bad diode in the alternator or does it sound like voltage drop.

curtie94

Is there any way to check for a bad diode with the alternator still in the car?

hondawhiz

your alternator is bad. or your battery is causing it to seem that way. check your voltage to your power cable while its disconnected from the battery. might need a new battery.

MAD_MIKE

Bad diodes would cause a flickering or pulsing of the headlights at night. If the voltage regulator was crapping out or not sensing the correct voltage it would not properly charge. At the battery when then engine is running you should have ~14.4V

Test the battery is fully charged.

12.65V 100% 1.265 g/cm3
12.45V 75% 1.225 g/cm3
12.24V 50% 1.190 g/cm3
12.06V 25% 1.155 g/cm3
11.89 V 0% 1.120 g/cm3

If when fully charged the battery only reads below 12.65 V then it is considered 'dead'.

curtie94

What do you mean by that? What are the steps.

nus_dogg

He might've mean to OHM test the power wire.