MXYguy

Hi folks,

I've been through the old threads and seem to be experiencing some strange combo of a few different issues, so I decided to start a new discussion. Please forgive the redundancy!

'85 extracab pickup 22R, internal regulator alternator. The electronics have been in steady decline for awhile now. It began with the temperature gauge, only working intermittently. Then the ignition switch - wouldn't stop buzzing unless in "lock" mode. Then the horn only worked when the steering wheel was turned to the right. Then the "Charge" and "Batt" lights started coming on intermittently - sometimes turning the blower on high would shut them off, sometimes not.

I only use this rig in the not-snowy months (I live in a remote part of AK) so it's been out of use since November. I started it up a few days ago and was putting air in a tire using a 12V compressor running off the cig lighter when....suddenly the compressor kicked up its speed and the charge and batt lights were on again. Got concerned so turned off the truck and checked under the hood, and the alternator was smoking. (This could be because my power steering pump has a minor leak and it was burning off stray fluid, which I know could be causing all these problems also, plan to fix this soon too!) I checked voltage from the alternator terminal B and it was fluctuating wildly, between 13 and 15.9. I thought for sure the alternator/regulator was bad, until....

I came back the next day to tinker with a few things. Started it up, now the fuel gauge doesn't work (did last time). Cleaned all the grounds, poked around the fuse box. STOP fuse blown, replaced, no difference, hasn't blown again yet. All other fuses are good. Now the alternator seems good, no smoke, is putting out a steady 14.6, (even under load which seems a bit high?), and the voltage at the IGN and CHARGE fuses is 14.3 (also high?). Drove it a couple of miles and the fuel gauge sort of works only when the rig is moving, but it's kinda drunk, staggers around a bit and doesn't reach full (I know the tank is full and doesn't leak). I checked the resistance on the fuel and temp gauges in the combination meter and they're right on spec as per the FSM, 55 ohms and 25 ohms respectively.

Do I have an issue with one or more circuits or is the regulator messed up and causing everything (or at least most of them)? Can the regulator put out a normal charge voltage and still cause problems elsewhere? I'm already bald so I don't have much hair to tear out over this one....... .......and I'm 150 miles from a parts store so I want to be as thorough about the troubleshooting as possible before I start ordering parts......and I don't want my truck to catch on fire!

osv

14.6 vdc is high, it should read 13.8-14.4 across the battery terminals... the compressor suddenly speeding up indicates a voltage surge??

are all of the ground wires in place? one off of the back of the head, one to the battery, etc.

MXYguy

Great suggestion on the ground on the back of the head, hadn't thought of that one. Checked it and it was slightly damaged, so I fabricated another one, cleaned everything up, and reinstalled. No change though. All other grounds I can think of are shiny and tight. I'm getting 14.6V at the battery, 14.72 at the alternator, and 14.3 at the ENGINE fuse.

Definitely seemed to me that some sort of surge happened when the compressor kicked up, which is why I suspected the voltage regulator. I've tried the compressor since then, and it seems to run normally. Doesn't have an effect on the rest of the system (CHARGE and BATT lights don't illuminate), and the CIG fuse is intact. I suppose with these schizophrenic electrical issues an intermittent symptom shouldn't be discounted when it isn't happening though eh?