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Discussion Starter #1
I've looked around the internet and there only appears to be anecdotal evidence surrounding this correlation.

Three times now, in the space of a year, my '99 4.6 Thor NAS has suffered an EAS error while driving in the rain. Twice I've simply reset with the EAS software and carried on once the rain stopped. I've crawled around inspecting stuff under the truck and noted that all of the height sensors are tight and clean, as is the fuse box (totally dry).

Tonight, I forgot that the truck had those issues and again driving in the rain, the EAS would not set the height, ie: the light just kept blinking at normal height. The truck did slowly raise and level out despite the blinking light. Any way, after about 15 minutes of driving, the TRANSMISSION FAILURE warning appeared, followed by a message about TRACTION CONTROL and then the gauges stopped working, the HVAC display shut off with only the back light visible. The headlights were also notably dim. The engine continued to run, but I discovered at the next traffic light, when trying to pull away, that the transmission might be stuck in a higher gear. I was able to limp the truck home and because I've fought with a dying battery before, I knew that many of the problems could be attributed to low voltage. I checked the battery and it registered 11.4v (battery charger currently in place). Despite having driven in the rain, under the hood its very dry, no moisture around the fuse box, battery or alternator. The truck has been very reliable for several years, save for the 3 instances I drove it in the rain.

I'm curious what the correlation is between the rain, the EAS and potentially a rapidly discharging battery. To me, it seems like the rain is affecting the voltage (pointing to a short?) which in turn degrades all the other systems. Is there somewhere that, upon getting wet would stop the alternator charging, stop the EAS from responding properly, cut out the transmission ECU and subsequently kill the gauges (tach) and HVAC?

There's a ton of knowledge here and I'm hoping someone can point me to a likely culprit(s).

Thanks in advance!
 

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the EAS would not set the height, ie: the light just kept blinking at normal height. The truck did slowly raise and level out despite the blinking light. Any way, after about 15 minutes of driving, the TRANSMISSION FAILURE warning appeared, followed by a message about TRACTION CONTROL and then the gauges stopped working, the HVAC display shut off with only the back light visible. The headlights were also notably dim. The engine continued to run, but I discovered at the next traffic light, when trying to pull away, that the transmission might be stuck in a higher gear. I was able to limp the truck home and because I've fought with a dying battery before, I knew that many of the problems could be attributed to low voltage.
Nothing to do with the EAS at all but a classic case of the battery not being charged while driving and going flat. The system is intelligent enough to shut things down as the voltage drops in an order that it considers them to be unnecessary. The Transmission Failure is due to the gearbox ECU seeing less than 10V so it goes into Limp Home mode.

If this was a GEMS, the cable from the alternator goes first to the starter motor and then to the secondary feed on the battery termina but a Thor has a direct cablel. Measure the voltage at the battery with the engine running and the voltage at the alternator output terminal. They should be the same or at least within 0.1V of each other. Otherwise, you need a new battery (although if it hasn't been changed in 3 years chances are you need a new one anyway).

The slow to fill on the EAS is caused by the same thing, low voltage, and if it does it in the rain it might point to the connection at the starter getting wet, although it could just as easily be water getting into one of the height sensors. When it has done it in the past did you read the faults before resetting or just reset them without bothering to see why it had faulted?
 

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Discussion Starter #3
Thanks Richard.

At this point I'm suspecting that the rain/eas connection may actually be a red herring. There is certainly a problem with my truck regarding the wet and the EAS, but at the same time, my alternator is not putting out any power.

I did as you suggested and found that once removing the charger, the battery showed 13.4 volts. I noted that there is no battery light when I turn the key and now there is a ALTERNATOR FAULT warning in the multifunction display. I started the truck and the battery reads 12.0v off of the posts. I also probed the B+ terminal on the alternator and it shows the same 12.0v regardless of RPM.

I confirmed that the charge light bulb is still working (D+ to ground) and I went one step further and temporarily installed a test lamp on the D+ and noted no change in the charge function.

I'm guessing a new alternator is in my future, hopefully my year old battery will hold up for a while longer.
 

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Unless you are using it for very short journeys, I suspect a new alternator is imminent. If you have a decent auto electricians locally you may find that they can (or you can) simply replace the regulator. This will give you new brushes too so as long as the slip rings are good, it'll be as good as new.
 

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Discussion Starter #5
I was wondering if these alternators were rebuildable like the Bosch unit on our old Volvos. I haven't seen the replacement parts available online.
 

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Discussion Starter #7
That's for the alternator up to '98, mine unfortunately needs parts for the '99-02. I found a replacement alternator for
$450... I'll consider that the car payment for this year, lol.

Thanks for the help Richard.
 

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Discussion Starter #8

I should have dug a little deeper, this might work!

I placed an order, $61 is slightly more palatable :cool:

Thanks once more...
 

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get a cheap USB socket too to put in the cigarette socket - good for keeping an eye on the voltage. Shd show c 12.8 at rest, and then will jump up when the engine is running, and then down again as you add HAVAC/ headlights. Just peace of mind - it fixes nothing of course
 
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