anyone have any idea why my speedometer, tach, a/c, alt won't charge and wait to start light just up and quit working???

 

check your fuses?

 

all the fuses checked out good and i also replaced the speed sensor on the transfer case still nothing. i know of the sensor on the rear diff. but that still don't make sence why the alt would stop charging at the same time.

 

sounds like a ground problem maybe

 

if its all of the above its most likely a ground wire loose or fell off

 

Heh... Just this last Monday. My truck just did the exact same thing. First thing I notice was no A/C (that's always the first thing you notice if you live in S.Texas) then I noticed it wasn't charging, then while I drove back home, notice no Tach reading and no Speedometer. Also, the wait to start light no longer lights up when you turn the key. And I'm betting the check engine light no longer works because the "on-off-on-off-on" keyturn thing give me nothing as far as codes. I found a webpage that says the old '94 are supposed to give off a computer code via the engine light, by doing that.... Either they are completely wrong, or my check engine light is broken...
94 Diesel Ram DTC's

My dad used to be a chrysler certified tech back in '00 (thru mid 70's; as far as I know although I guess as far as the official test and patch goes, probably mid 80's) turned used car salesman for a while and is just now going back to mechanic'ing (guess he missed it, or got tired of dealing with dead-beats, and long hours, with no Saturday's off); anyway he tried hooking up one of those diagnostic tool things to it, but got no codes from it. He figured, maybe, the one he has wasn't compatible or something. Said he tried everything he could think of, but still can't figure out whats broken and really doesn't want to randomly try parts (or at the very least, We don't want to pay for trial and error part changes.). He wants me to take it to the dealership that he used to work for and via personal channels have an old friend of his, do a diagnostic with a real diagnostic tool. Not some 3rd party type that my dad has availiable to him...

Anyway, I plan on doing that this coming Monday.... Going to try to get the truck in there via an old recall order thru a service writer friend we both know. And his other friend will plug in the diagnostic machine while it's in their parking lot. Hopefully meaning I won't have to give the dealership a penny. But we'll see how that goes; if I end up having to pay something for the recall visit, well then I'll have to pay something.

Anyway... long story short, I'll have an answer for this question when I get one myself. My dad suspects it's the computer.... FCM, PCM? (whatever it's called). Which run about 350-600 bucks...(depending on where you get one). And I'll bet that's what it ends up being...

 

The way the circuits are in cars, a ground that seems unassociated with the problem circuit can be throwing all kinds of problems with several different systems. Check the ground blocks and start chasing wires. If someone has stabbed a wire with a multimeter probe during the truck's life then it is highly likely for that wire to corrode enough to cause the problems you're having. A little time with a meter and I bet you can isolate this thing.

 

I've already told him about your ground suggestion and he's already deduced that it isn't the ground, in my case. I got kinda lost in what he was telling me and basicly just kept nodding my head and probably absorbing a quarter of what he said. He told me that he spent about 6 hours working on my truck (which basicly translates to... all day). He said that the tach, charging system, A/C compressor, are all tied into each other, because the computer is reading no RPM's which leads to it deciding that you don't need any charging, and don't need the clutch to engage for the A/C... So, as far as the computer is concerned... the truck ain't running and doesn't need any of that stuff.

He basicly said that one of the lines coming out of that computer isn't putting off enough volts. Think he said it needed 8 volts and he's only seeing 4.5 volts. And he even tried to fool it with a regulator or something to increase the voltage to around 9 volts, but the computer was too smart for that... didn't work.

He then went on and told me that he could just bypass the computer and get my A/C working and the Charging system working, no problem.... but I woudn't have a speedometer or a tach... nor a working odometer for that matter. But... Waaaa I don't want that. I want to see the needles move around when I drive. Besides more realisticly, I don't want to get any speeding tickets.

Imagine that conversation...
"Know how fast you were going, sir....."
"Umm.. No.... Speedometer doesn't work...."
"Oh it doesn't huh? here's your other ticket...."

Then there's that little matter of inspection sticker.... Even though I have about 7 months to worry about that... Anyway, I'll have the answer to my problem by next week's end, I'm sure. Even though he suspects it's that computer that conked out.

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I registered, and made that first post, mainly because, misery loves company; and he had the exact same misery as I do. Although, he got his weeks earlier and on a newer truck.

I know I wouldn't be writing any of this if it didn't just happen to me, causing me to search Yahoo.com for answers.... and finding this forum, by mostly, accident.... And well... might as well chime in and say I got your problem, too. Afterall, had no luck finding anything much else on the subject.... of no A/C, no Charge, No speedometer, and No tach....

Funny that 2 days ago I didn't even know this forum existed.... IGN and Gamespot forums are the only ones I waste time on. Strange how things work out. Although, then again, I most likely won't end up sticking around. Not very much I can contribute to a forum like this... I'm not really a gearhead.... I'm only a son of a gearhead. The last thing he wanted me to do was follow in his footsteps. Even though, in his prime, he made about 40k more a year than I do, now... (at the same age, he was then....)

Of course, then again... He's gotten a few close calls... He once told me a story where a compressed suspension spring, by pure luck, missed hitting him straight in the chest, because he just happened to turn away as it sprung out of it's compressor tool thing, striking a wall behind him.... and other such stories.

 

Good luck with your problem, the electrical side of these trucks can be a real pain, and welcome to DB!

 

okay... got it back from the dealer on Tuesday. No luck there, Tech there couldn't talk to the computer, either. So, ended up buying a new one from a salvage yard for around 200 bucks. Everything works fine, now...

So, that was the problem, computer died on it....