Electrical?

TylerMoore · January 5, 2008

everytime when i get into the gas at aroung 4000rpm the battery meter will start to drop the lights dim way down and the battery light comes on. Let off the gas everything is fine. I have checked the alternator and it has been replaced roughly 8mths ago and the battery about a year ago. Any ideas on what to do? The DTC's is a P1637 GENERATOR L-TERM CIRCUIT have no clue what that means

rjirvine · January 5, 2008

It means there's a fault in your charging circuit.

I would check the terminals and wiring at your battery and the alternator. Something may be loose or burned. If that looks okay, I'd take it to your local parts place and see if they can put the generator on the tester.

From the book:

"A generator fault, such as a shorted output diode, malfunctioning regulator, open or shorted rotor may cause a low battery charge."

superjim · January 5, 2008

everytime when i get into the gas at aroung 4000rpm the battery meter will start to drop the lights dim way down and the battery light comes on. Let off the gas everything is fine. I have checked the alternator and it has been replaced roughly 8mths ago and the battery about a year ago. Any ideas on what to do? The DTC's is a P1637 GENERATOR L-TERM CIRCUIT have no clue what that means

the "BATTER NO CHARGE" message will set when the "L" terminal is shorted to ground. In plain english, on the back of your alternator there is a wiring harness and connector attached to it. The connector has 2 wires, designated the "F" and "L" terminals. The "F" terminal reports the output voltage back to the computer (PCM). The other wire, the "L" terminal, reports the alternator output voltage to the Instrument Panel Cluster (IPC).

Somewhere along the pathway from this connector on the back of the alternator, to your IPC, the wire has shorted to ground.

Check to make sure it's not a wiring harness short to ground from rubbing, or corrosion buildup on a connector

Check the alternator! It may just be that the voltage regulator is failing and shorting out to ground - not uncommon. You would not see this with a simply cigarette lighter plug-in alternator analyzer, as those just check system voltage. For a complete alternator diagnostic, take it to a shop or pull the alternator and take it in to be bench tested at the auto parts store. You may just have a bad alternator or regulator.

Jim from Texas