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Roy
Roy, import/domestic specialest
Category: Car
Satisfied Customers: 4632
Experience:  ASE master tech for 40 years
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I have a 1993 Isuzu Rodeo #.2L 4x4 last night I was about 70

Customer Question

Hello,
I have a 1993 Isuzu Rodeo #.2L 4x4 last night I was about 70 miles from home at a friend’s, I left drove about 10 mins and stopped at a gas station. Walked in used the facilities and returned to the car.
After starting it, I noticed all the dash lights that are on just prior to starting were still on and the volt meter was showing no charge. With the headlights on, I shut the engine off to see if they went dim, they did not. I checked the belts all was good, checked fuses, all was good. I drove home, thankfully I have a larger battery in the car than stock and it ran the lights long enough to get home. On the way home I noticed I also did not have the blower fan for heat. I made it home got in the garage and started snooping around. I checked relays under the hood and fuses.. I checked all the relays with 12 volts to confirm function and checked for resistance to confirm that upon activation, I did in fact have the circuit,, they all tested fine. However I noticed when I removed the charge relay that the dash pre run lights all went out and the fan had power,, put the relay in and the problem resumed. I pulled the fused for the ecm and put it in block learn mode and started it,, it re-learned the block just fine. So I’m hopefully that the ecm is not the issue. I was thinking of a shorted generator ( the factory shop service manual says this does not have a alternator, rather a generator. And I can only find alternators at the parts stores, I may be in trouble if that’s the case), but it also seems like maybe the ignition switch kinda like stuck in the start position , yet is letting the car run?? I have always noticed when I start the car, the fan does stop while the key in is the start position, then when you let off to the run position the fan resumed… do you have any ideas,,, generator? Ignition switch? Help LoL
Submitted: 1 year ago.
Category: Car
Expert:  Roy replied 1 year ago.

most people refer to alternators but they are generators. they are one and the same.

yes, if the charge light is on along with the brake light, the alternator has failed. and needs to be replaced.

Roy

Customer: replied 1 year ago.
ok i will change it out in the morning.. just to clarify.. the charge light goes out.. only the volt meter shows no charge activity.. i was questioning the ignition switch because of the heater fan being out as well.. it is only the items that would normall be powerless when the key goes into the spring loaded start position that are dead. perhaps this model year just has all of that on the same circut? i will find out tomarrow, it should not take but an hr or so to change out the Alt thank you for your ideas
Expert:  Roy replied 1 year ago.

to be sure, use a voltmeter on the battery with the engine running. it should be 14 to 14.5 volts

Roy

Customer: replied 1 year ago.
ok this just got very interesting.. i checked your idea at the battery,, i jump it off a fresh battery and then took the jump cables off. i show 10 and half volts. so i shut it off and was getting ready to remove the alternator, and i got curious,, so i took the leads off and pushed rubber hose over them to keep them from grounding off, and tried starting the car, it did start so i put the volt meter from ground to one of the terminals,,, nothing ground to the second terminal showed 14volts. i think i need to read a book on Alternators..i was under the impression it would not run if it was unhooked,, much less create the voltage... but when the wiring harness is hooked too it,, where is the voltage going at that point
Expert:  Roy replied 1 year ago.

running the truck with the alternator disconnected tests nothing. your systems along with the alternator need 12 volts to work.

10.5 volts is no good. the battery needs to be charged and then repeat the test

Roy

Customer: replied 1 year ago.
ok, so this morning i pulled the alternator off and took it to Napa and had it bench tested,, i did not wach the test but they said under load its puting out 14 volts up to 60 amps. so i picked a new one up regardless, new not reman'd. i stopped by the honda dealer and asked them about a test procedure for the ignition switch some old tsb's for a 94 passport was all they had, but the body and engine on those is the same as the rodeo, the ignition switch tested fine according to the tsb procedures. i mounted the new alternator and still have the same problem as before. so i dont know whats wrong with it, but its not the alternator. returned the new one to Napa and re installed the one i had that tested fine
Expert:  Roy replied 1 year ago.

I am at work, will get back to you in the morning

Roy

Customer: replied 12 months ago.
ok so it has been a few days sense you said you were going to get back to me... do i interpret this that you have no further suggestions or answers or that you are researching the issue further
Expert:  Roy replied 12 months ago.

sorry, have been sick. just rying to catch up.

have you checked for power to the alternator???

Roy

Customer: replied 12 months ago.
It has currently 12volts the same as the battery. I also pulled the neg off the batter and checked from the main fuse in the relay box to the me term of the battery and have the same 12volts. So it would seem all the connections are good and no voltage drops.
Expert:  Roy replied 12 months ago.

ok, what is the voltage with the engine running???

Roy

Customer: replied 12 months ago.
Still the same at the battery. 12volts
Expert:  Roy replied 12 months ago.

ok, I attached a wiring diagram for you to check. there are 2 fuses in the under dash fuse box. check them with a test light or voltmeter for power on both sides.

Roy

Customer: replied 12 months ago.
All the fuses are good, the 10amp Engine L fuse shows no power with the key on or off.. i may well be at the root of the problem now, in that i dropped the panel to look behind it to see why, and i found a horriable mess of wiring, appereantly at some point there was a anti theft system on here. i am guess that only because some of the wiring is spliced into the ignition switch to disable the starter. This will take some time to get this all removed at put back to factory connections, and i have a feeling in doing so im prolly going to find a shorted power wire somewhere. i will update this when i get finished, but for now its vacation time for a week
Expert:  Roy replied 12 months ago.

ok. please dont forget to rate me as it is the only way I get paid for my efforts

Roy

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