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dlboarman · 07-02-2015, 02:31 PM

I have what I think is a strange problem. Several months ago the alternator on our 2001 Journey DL froze up… at least that is what the repair people told me. I do know it ate the belt when I pulled it from storage so it makes sense the alternator refused to turn any longer. It probably was the original so it had done its duty.

The repair shop, who works on Freightliner equipment, replaced the alternator. When I used it, I noticed the alternator light came on, several times. Eventually, I realized the light was only coming on when the transmission was in reverse. However, after a longer trip it also came on occasionally when I was driving down the road. So, back to the repair shop. They said it was a bad alternator and replaced it again.

Fast forward another month or so and on the way from SC to WV, the light began to come on and then go off. Eventually, it just came on solid. This continued for several hundred miles. I realized the voltage gauge was slowly dropping. I called Freightliners emergency help number and was told the alternator was probably not charging and when the voltage from the batteries got low enough the gauges would quit working and then the engine and transmission ECM would begin to act up. My words, not theirs. This is exactly what happened. I managed to get to a RV repair place (lucky, lucky) and the guy there diagnosed it quickly as probably a broken wire. He found that the wire from the engine ignition switch had been crimped and then broke. He spliced it and put shrink wrap around it. And it worked great for the rest of the trip … except when I put it in reverse, the alternator light still comes on.

I am looking for ideas to point the repair people to the solution to this before it costs me more money.

38Chevy454 · 07-02-2015, 02:36 PM

That is kind of strange. Only thing I can think is the reverse light circuit is somehow interrupting the exciter circuit for the alternator.

TQ60 · 07-03-2015, 09:46 AM

Comes on every time?

Give it some throttle and see if it goes out.

Possible that in reverse engine rpm drops and alternator output follows.

Jim_HiTek · 07-03-2015, 09:53 AM

Is there a diode between the ignition switch and the alternator?

There may be a diode soldered inline with the voltage supplied to the alternator (Field voltage). If that diode is shorted, which is possible if the wire break was sputtering for a while, then I think that will cause your symptom. The diode is suppose to prevent voltage feedback.

Note not all RV alternators have that diode so checking your schematic is the first step.

dlboarman · 07-26-2015, 06:09 PM

I tried increasing the rpms and the light stays on. Once I put it in drive, the light goes out.

Gary RVRoamer · 07-27-2015, 08:05 AM

Very strange. It acts as though the exciter current to the alternator is being pulled from a wire associated with the gear shift position (Drive vs Reverse) rather than simply the Ignition (should be tied to ignition On). What does it do when in Neutral? Park?

I think you still have a problem with that wire that was "fixed".

dlboarman · 08-28-2015, 02:56 PM

The problem is still with me... and the light only comes on in reverse. Not in park, or neutral... or typically, not in drive. It always comes on in reverse within a couple of seconds of putting the shift into reverse.

Dutch Star Don · 08-28-2015, 05:18 PM

I'm hesitant to mention this, but every time I read this it reminds of older vehicles. When placed in reverse, if often caused the idle to lower and make the alternator light come on. Silly, question, but what is your idle set at.

I don't think Winnebago Journeys came with a Smart Wheel, but if it does have one, many don't realize you can accidentally lower the idle over time at the steering wheel. The cruise allows the idle to be lowered or raised 25 rpm at a time.

dlboarman · 08-29-2015, 08:20 AM

I also assumed this might be the issue... low idle I mean. So, in reverse I increased the rpms (fast back up) and the light stays on. The repair shop asked about this too. It appears to have nothing to do with idle speed.

cimplexsound · 09-02-2015, 04:50 PM

Use a multimeter and test the voltage at the chassis battery terminals. The voltage should be 14.50 volts DC when the motor is running, and 12.50 volts when the motor is off. I voltage reading below 14 volts while the engine is running could be early signs of alternator failure. This will trigger your alternator light. So if this happens have the alternator tested.

1979 Dodge Tioga Class C 24 foot. 1987 Fleetwood Bounder 34 Foot.

jrocker · 09-03-2015, 08:43 AM

Check your bulbs for the back up lights.

It sounds a bit silly, but it's worth a look.

A couple of years ago I had a problem with a Chevy van. On my way home from work, after a long night, my headlights and dashlights would flicker and sometimes go completely out. All the while, flashing and flickering the check engine light.
I shelved the van and rode the motorcycle for the rest of the week and spent the weekend chasing ghosts. Never found a thing. Monday afternoon, I went to do one last poke around before I gave up and took it to the shop when noticed a tail light was out (specifically, the brake light). I replaced the bulb and all was well.
After some research, I found the root cause. Because of the fixture, the filaments in the bulbs were horizontal for this vehicle, so when the brake light filament broke, the broken end would drift down to the running light filament, thus causing a short. So every bump I hit in the road caused the filaments to touch, until finally the filament got hung up in the other and caused flickering to become a complete outage.
Now, the back up light is likely a single filament bulb, but there may be a short somewhere in that circuit. So, if the bulbs are good, and the fixtures free of water, maybe chasing the wires all the way to the fusebox could bring the short to light.