Help, help - 72 Blazer almost left me stranded again.....

[homemadesin]

The first time it left me stranded was about a month ago. I bought the K5 from a SoCA guy and brought it to CO. In November, we had a severe cold front come through and create a sheet of ice everywhere. Traffic was creeping and I started to notice that the lights were slowly getting dimmer and dimmer. The fan was about to stop, no heat, no lights, so I turned the lights off - to see what happened. When I turned them back on, everything went dead. Of course being the first cold front of the season, I didn't have squat in the car (no tools, no lights, nada /forums/images/graemlins/blush.gif
So I left the beast and came back with new battery. Couldn't make it to work and back to home before it happened again. Towed it to work and eventually replaced the alternator (another 63A POS) and regulator, and a couple of inline fuses. Started and ran great.
Fast forward to today. We've had moderate weather since the prior incident. Snow today, but no ice to speak of. Ever since the death episodes, I watch the voltmeter constantly. I noticed it never got to middle, even when revved. Sure enough, the lights started getting dim. fortunately, I could maintain full speed (75-85 mph) all the way home with no delays, but zero help from the headlights towards the end. What the hell could be wrong now? I noticed during my electrical clean-up that the wires were brittle, but I'm not ready to blame them just yet. any ideas? This is my daily driver (50 miles a day) and I just don't have the heart or time right now to do a complete wiring job..... /forums/images/graemlins/confused.gif

 

[Triaged]

Do you actually have a volt meter installed?...stock they come with a ammeter.

It sounds like there is something wrong with the alt. again. Only other thing could be really bad wires or bad grounds.

 

[Tuff]

I had a a problem close to that. I wasn't ready to put in a new wiring harness either. I kept replacing parts and wires. Finally I changed out the voltage regulator and I have not had a problem since. With these old trucks it could be anything. It only cost me like 10 bucks though, so you might want to try it.

 

[homemadesin]

Yeah, ammeter.

I have already replaced the voltage regulator at the same time I did the alternator. I almost went for the mega 300A alternator with self exciting regulator. Instead, I bought a cheap NAPA unit and regulator for a total of $50 or less.

I just can't imagine the regulator going so soon (1 month??)

 

[RingMaster4x4]

I had the same problem. My problem was bad wiring. The wire that tells the regulator to turn on and off ( I call this wire the remote wire) was bad so I cut it off at the regulator and ran it inside the cab to a toggle switch so I could turn it on and off. This worked for me untill I got a alternator with the build in regulator.

 

[fatdog]

I lost two regulators and one alternator in a 6 mo. period on the 71 GMC. I can't help question the quality of the external regulators. Anyway, I decided to just change to the internal regulator alternator. I bought one at Autozone for $39 (had a core) along with the plug terminal for another $3. It solved my problems. If you do this you may already know how, if not, this is how I did it. (Alternator end) red on plug to red in harness to alt. pos. terminal. White on plug to white in harness. Black to ground as before. Abandon blue. (Regulator end) Jump white and brown together to complete loop and make stock amp gauge work.

Later, Rob

 

[Stroked72Blazer]

It's not uncommon to get a bad altenater from the parts store. Though this usually happens at Autozone not Napa I sappose its possible. Your altenater should still be under warranty so replace it to see if you just got a bad one or not. This time when you do it look at the old one to see if it spins smoothly (you are wanting to check the bearing) if it feels rough then you probably either overtightened your belt or your puillies don't quite match up (check this before you pull it off as just the slightest misalignment will destroy bearings fast). Check your battery to see if it is leaking If so your regulater was the problem and caused the altenater to overcharge. Another posible problem is if you have much aftermarket electronics in the truck such as stereo, engine management, C.D. Ignition, electric fan, Nitros control system...any thing like this can overwork a stock altenater and cause it to wear out prematurely, especially if you have more than one add on.. These are just some guesses based on my experiance and should let you eliminate some posabilities before you go replacing wiring harnesses.

 

[gtkustoms]

you could just sell it to me /forums/images/graemlins/grin.gif and then you will not have to worry about it.

 

[homemadesin]

gtk: I hope it doesn't get any worse or I may sell it one day...

BTW it was the voltage regulator! I went to NAPA and picked one up for about $45. Compare that to the $13 unit I got from Advance that lasted about a month. No more Advance Auto for me!