Is My Electrical Diagnosis Correct?

Hi, I have five questions (below). Both the blower motor and radiator fan
for my '91 Chevy Cavalier 2.2 liter no longer work, even though I replaced
both motors last week. The 25 amp AC/Heater fuse blows every time as soon as
I turn the key to "run" with the heater on. I must have a short.

After studying the wiring diagram, it seems the radiator fan and blower
motor are on the same circuit.

The wiring for this circuit goes as follows:

Wire from Ignition Switch to
25 amp Heater/AC Fuse

Then from this Fuse, wire to Splice A, with two wires coming out of this
splice (wires 1 and 2 below):

Splice A Wire 1:
From Splice A to
Heater Control Switch then to
Blower Resistor then
through the firewall then to
Splice B: one wire to blower motor and the other to the blower relay

Also, redundant ground from Blower Motor to Main Ground at Tranny Bolt

Splice A Wire 2:

From splice A through firewall then
to Coolant Fan Relay then
to Alternator input sensor

[end]


QUESTION 1:
So does this mean the short must be between Splice A above and the ignition
switch?

QUESTION 2: If so, why does my alternator still work then, since that is
also at the end of this same circuit??

I am at my wits end, as I was forced to purposely break my plastic center
console in multiple places, just to access the blower motor switch. I was
considering taking a Sawzall to it to get enough access. See, my shift stick
knob would not come off, even though I pulled out the U-Pin. So I had no
choice but to break the console into pieces to get to the blower switch.

QUESTION 3: How do I get my shift stick know off if it is stuck on?

Then, I was not able to perform the Chevy recommended diagnostic procedure
with my DMM, since as soon as I turned the key to run, the fuse blew!

And it is almost impossible to inspect the wiring, since the clusters are
completely wrapped in electrical tape and very hard to access, even with the
panels off, due to a metal support frame. It would take my hours just to
remove the tape.

And there is molten lava-like black gunk covering everything where my wire
harness enters through the firewall. I thought is was dirt, but it feels too
rubbery. It prevents me from seeing the wires at some points.

QUESTION 4: What is this gunk?

And now I have to remove the glove box and passenger side trim to access the
blower resistor.!

QUESTION 5: When will all this insanity end? All this just to find a short?!


Thanks for any help!

Julie

"Julie P." > wrote in message
news:74Off.5376$BC2.2@trnddc04...

> QUESTION 3: How do I get my shift stick know off if it is stuck on?
>

Shift Stick KNOB!

"Julie P." > wrote in message
news:74Off.5376$BC2.2@trnddc04...

> QUESTION 3: How do I get my shift stick knob off if it is stuck on?

Usually there is a horseshoe or staple shaped clip that holds the knob on.
It usually goes on the front of the knob, where it is not easily seen.. If
yours
is of this ilk, just pry it out and the knob should come off.


I will try to reconstruct your schematic and make a guess.

> wrote in message
. net...
>
> "Julie P." > wrote in message
> news:74Off.5376$BC2.2@trnddc04...
>
>> QUESTION 3: How do I get my shift stick knob off if it is stuck on?
>
> Usually there is a horseshoe or staple shaped clip that holds the knob on.
> It usually goes on the front of the knob, where it is not easily seen..
> If
> yours
> is of this ilk, just pry it out and the knob should come off.
>
>
> I will try to reconstruct your schematic and make a guess.
>

Thanks HLS. But I did take the U-clip off. And the knob was still stuck on
the stick. Should I just yank on it with all my strength (without trying to
hold the stick down)? Will I damage the tranny? Or will I yank the stick out
fo the tranny if I did this?

Julie

"Julie P." > wrote in message
news:08Pff.1541$Vu2.190@trnddc06...

> Thanks HLS. But I did take the U-clip off. And the knob was still stuck on
> the stick. Should I just yank on it with all my strength (without trying
to
> hold the stick down)? Will I damage the tranny? Or will I yank the stick
out
> fo the tranny if I did this?
>
> Julie

Although I am not familiar with this Cavalier application, GM normally just
uses the
U clip retainer, and the knob should come off. I havent noticed before that
the park
release button gets involved in holding the knob on, but you could try
gently pulling
and twisting while working that button.

If you got really heavy handed, I guess you could always damage the shifter.
But I
think it is rather unlikely.

I have a Chiltons or somesuch which applies to a number of GM cars, and will
take
a look a little later today to see if GM engineers have come up with some
change
in the setup.

> wrote in message
om...
>
> "Julie P." > wrote in message
> news:08Pff.1541$Vu2.190@trnddc06...
>
> > Thanks HLS. But I did take the U-clip off. And the knob was still stuck
on
> > the stick. Should I just yank on it with all my strength (without trying
> to
> > hold the stick down)? Will I damage the tranny? Or will I yank the stick
> out
> > fo the tranny if I did this?
> >
> > Julie

Re the stupid Chiltons, it was worthless. Sorry.

> wrote in message
om...
>
> > wrote in message
> om...
>>
>> "Julie P." > wrote in message
>> news:08Pff.1541$Vu2.190@trnddc06...
>>
>> > Thanks HLS. But I did take the U-clip off. And the knob was still stuck
> on
>> > the stick. Should I just yank on it with all my strength (without
>> > trying
>> to
>> > hold the stick down)? Will I damage the tranny? Or will I yank the
>> > stick
>> out
>> > fo the tranny if I did this?
>> >
>> > Julie
>
> Re the stupid Chiltons, it was worthless. Sorry.
>

No problem HLS. Thanks for looking! I'll try wiggling around a little, but I
can tell you it is stuck on pretty tight.

Julie
>

Just a thought for you.

On the last heater blower I bought, the power plug was a 'universal' one
that could have the negative in either of the two pin positions. If I
had of gotten it wrong, I would blow the fuse instantly like you are
doing.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Aug./05 http://www.imagestation.com/album/in...?id=2120343242
(More Off Road album links at bottom of the view page)

"Julie P." wrote:
>
> Hi, I have five questions (below). Both the blower motor and radiator fan
> for my '91 Chevy Cavalier 2.2 liter no longer work, even though I replaced
> both motors last week. The 25 amp AC/Heater fuse blows every time as soon as
> I turn the key to "run" with the heater on. I must have a short.
>
> After studying the wiring diagram, it seems the radiator fan and blower
> motor are on the same circuit.
>
> The wiring for this circuit goes as follows:
>
> Wire from Ignition Switch to
> 25 amp Heater/AC Fuse
>
> Then from this Fuse, wire to Splice A, with two wires coming out of this
> splice (wires 1 and 2 below):
>
> Splice A Wire 1:
> From Splice A to
> Heater Control Switch then to
> Blower Resistor then
> through the firewall then to
> Splice B: one wire to blower motor and the other to the blower relay
>
> Also, redundant ground from Blower Motor to Main Ground at Tranny Bolt
>
> Splice A Wire 2:
>
> From splice A through firewall then
> to Coolant Fan Relay then
> to Alternator input sensor
>
> [end]
>
> QUESTION 1:
> So does this mean the short must be between Splice A above and the ignition
> switch?
>
> QUESTION 2: If so, why does my alternator still work then, since that is
> also at the end of this same circuit??
>
> I am at my wits end, as I was forced to purposely break my plastic center
> console in multiple places, just to access the blower motor switch. I was
> considering taking a Sawzall to it to get enough access. See, my shift stick
> knob would not come off, even though I pulled out the U-Pin. So I had no
> choice but to break the console into pieces to get to the blower switch.
>
> QUESTION 3: How do I get my shift stick know off if it is stuck on?
>
> Then, I was not able to perform the Chevy recommended diagnostic procedure
> with my DMM, since as soon as I turned the key to run, the fuse blew!
>
> And it is almost impossible to inspect the wiring, since the clusters are
> completely wrapped in electrical tape and very hard to access, even with the
> panels off, due to a metal support frame. It would take my hours just to
> remove the tape.
>
> And there is molten lava-like black gunk covering everything where my wire
> harness enters through the firewall. I thought is was dirt, but it feels too
> rubbery. It prevents me from seeing the wires at some points.
>
> QUESTION 4: What is this gunk?
>
> And now I have to remove the glove box and passenger side trim to access the
> blower resistor.!
>
> QUESTION 5: When will all this insanity end? All this just to find a short?!
>
>
> Thanks for any help!
>
> Julie

"Mike Romain" > wrote in message
...
> Just a thought for you.
>
> On the last heater blower I bought, the power plug was a 'universal' one
> that could have the negative in either of the two pin positions. If I
> had of gotten it wrong, I would blow the fuse instantly like you are
> doing.
>


Hi Mike, thanks for the idea! My blower motor has only one terminal though,
a positive one. The other negative terminal bolts on the motor housing (it
is a redundant negative connection which you do not need for the blower
motor to run), and I reused it on the new one.

Oh, and btw, on the brand new AC Delco oil sender I installed last week, it
came with some type of hardened pipe dope on the upper threads. I looked
like tape, but it was some kind of dried gunk. I installed it, and my
starting oil pressure is now up to 75 psi! It goes down after driving a
while, but not as low, or at least not as fast. My horsepower also seems to
have increased since I did this! It is easier to climb hills now.

I only wish I knew the torque for this. I kept turning it tighter and
tighter but did not want to go too far, in far of stripping the threads.

Oh, and next weekend, I am pouring carburetor cleaner into my engine and
will let it soak for 4 days. Then I will drain it and add oil, run it for 15
minutes, then drain it again. This will fix my low oil pressure! If not, I
will try 20W-50 oil, although I am worried it will be too viscous for the
winter.

Julie

"Julie P." wrote:
>
> "Mike Romain" > wrote in message
> ...
> > Just a thought for you.
> >
> > On the last heater blower I bought, the power plug was a 'universal' one
> > that could have the negative in either of the two pin positions. If I
> > had of gotten it wrong, I would blow the fuse instantly like you are
> > doing.
> >
>
> Hi Mike, thanks for the idea! My blower motor has only one terminal though,
> a positive one. The other negative terminal bolts on the motor housing (it
> is a redundant negative connection which you do not need for the blower
> motor to run), and I reused it on the new one.
>
> Oh, and btw, on the brand new AC Delco oil sender I installed last week, it
> came with some type of hardened pipe dope on the upper threads. I looked
> like tape, but it was some kind of dried gunk. I installed it, and my
> starting oil pressure is now up to 75 psi! It goes down after driving a
> while, but not as low, or at least not as fast. My horsepower also seems to
> have increased since I did this! It is easier to climb hills now.
>
> I only wish I knew the torque for this. I kept turning it tighter and
> tighter but did not want to go too far, in far of stripping the threads.
>
> Oh, and next weekend, I am pouring carburetor cleaner into my engine and
> will let it soak for 4 days. Then I will drain it and add oil, run it for 15
> minutes, then drain it again. This will fix my low oil pressure! If not, I
> will try 20W-50 oil, although I am worried it will be too viscous for the
> winter.
>
> Julie

I wouldn't jump up that high in oil viscosity. You say you use a 5W30
now I think it was, I would just go up to a 10W40 or even 10W30 for the
winter. I use 10W30 in both of my engines year round and they see -30
and colder.

And the blower does need the extra ground otherwise it will overload the
harness or body ground.

How about the new fan motor? Was the plug only one way on it too?

I would start unplugging things. I would start with the heater motor
and see if the fuse blows, then unplug the fan, then the fan sensor.
Or do all 3 and see then start plugging things back in.

The heater switch is mounted in plastic and is unlikely to short. The
heater resistor is mounted in plastic I believe and hard to short also,
but if it is in a metal box, then it could blow to a short.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Aug./05 http://www.imagestation.com/album/in...?id=2120343242
(More Off Road album links at bottom of the view page)