Hi everyone. I'm having a tough time and hope someone can help me. The fusible links to my ac (running from the alternator on the passenger side) keep blowing. I bought a new voltage regulator from rock auto but it is not where the manual says it is. I've searched on here and read it is in the control panel, but not sure where that is. Can anyone help or post a pic? Perhaps I have the wrong regulator?

 

92-93, the regulator is in the PCM or whatever name people wish to call it. It is behind the battery.
There are instructions in the FAQ section on how to install an external regulator.

 

What is the voltage at while it is running?

 

Fuseable links don't blow from voltage, they blow from resistance. A short circuit or a quick short to ground. Your A/C compressor clutch could have a short in it but I don't think it is the voltage regulator. A voltage reading would help us to help you.

 

As always, this forum rocks. The weird thing is the voltage sways alot when I first start the truck. Going off the volt meter in the truck, id say it ends up roughly 2/3 of the way to the right after it stops swaying. I don't have a voltmeter so I can't give an exact measurement. Not sure if it matters, but the links blow from just the vent being on...

 

Sure it's not your grid heaters kicking on and off making it sway? Mine does it when i start it cold. The volt gauge drops then goes back up and you can hear a loud click, the click is the grid heater relays. they draw alot of juice

 

yep classic grid heater coming on and off stops after about five min
thats why you have the wait to start signal below 40 degrees
and the large batteries .
the truck batteries must be double AA according to my eight year old cause their the biggest way bigger than the triple aaa

 

That's good to know...maybe the links are blowing from a short in the fan motor then

 

It is possible that the internal voltage regulator is shorted and is full fielding the regulator causing very high voltage, but very rare. If you have narrowed it down to the blower causing it, the next step is to get a multimeter and verify your diagnosis. Double check the battery voltage, make sure it doesn't go over 15 volts with the truck running, then you should test the current your blower draws on high. It shouldn't draw much more than 18 amps max. A new healthy one should be about 16 amps. Much more than that and they start barbecuing blower resistors, blower switches, ignition switches and their connectors. If it's really bad, it can take out fusible links, like you are experiencing.

 

The most common cause of fusible link failure is a dead shorty.

1. "Mechanic" screwing up. Most of us have been there.
2. Harness chafing causing a short to ground. Actually another version of #1.
3. A dead short in an operating solenoid, AC clutch, etc. Usually pretty easy to find with an ohmmeter.

When the engine is cold, the grid heaters cycle. The gauge is probably scaled from 8V (left side end of scale) to 18V. The grid heaters draw about 220 amps. The alternator puts out about 60 amps at idle, 120 when running. Under those conditions, voltage swings from 11.5V to 14.5V would be perfectly normal, thus we all see the voltmeter swing wildly for a few minutes after a cold start. I must admit it was a little unnerving when I first saw it.