Voltage Drop

[Century145]

My 1985 GMC Vandura's voltage meter is dopping into the red and the heater/air
cond. blower is not working. I replaced the battery and alternator and it
still is dropping! Does anyone have any ideas on what might cause this?

Thanks
Brad

[Alan Illeman]

Century145 <century145@aol.com> wrote in message news:20030622235033.14279.00001123@mb-m02.aol.com... My 1985 GMC Vandura's voltage meter is dopping into the red and the heater/air cond. blower is not working. I replaced the battery and alternator and it still is dropping! Does anyone have any ideas on what might cause this? Thanks Brad

You must have a short somewhere. With a voltmeter and the engine off,
check the battery voltage with one lead disconnected and then check it
with the lead replaced. There will be some voltage drop difference but
a small one at that. Report back here.

[451ctds]

I'd say bad body ground, based on heater blower not working. My 84 El
Camino did that a lot, blower out, voltage dropping at traffic lights, dim
lights. What I did was run a Ford starter cable from block to frame rail,
and
moved negative battery terminal from alternator bracket directly to engine
block. Chevys use a pathetic jumper
wire that goes from battery cable to fender to ground body. For the
ultimate in grounding pleasure, run a jumper wire from frame rail to
radiator support, as for alternator, be sure brackets are cleaned to bare
steel where alternator touches bracket, a poorly grounded alternator will
soon be a dead alternator.

Once you are properly grounded, test throwback voltage using a VOM right
on battery terminals. Test voltage, start engine, voltage should climb with
engine running..