jryder.10@gmail.com

Hey all... after having recently replaced a power transistor to get
what I thought was a blown blower ($$$$) I thought that my winter heat
woes were solved, now that the air was back to blowing... But when I
start it up, the temp display works fine, I can adjust the temp no
prob. Minutes later I see the temp display go from what I set it to, to
flashing "08" then the original temp I set, then "08" again! And I hear
the vent door motors start actuating, but NO heat comes out. Just
ambient air. I've tried looking everywhere for what this "08" means but
I cannot find any info.
The guy that sold my Pop's the car told us it was a temp sensor,
namely the one in the main vent... so I disassembled the whole dash,
found it and tested it's resistance with a voltmeter. It increased
/decreased resistance as it should when I would blow warmer/colder air
on it. So I know it's working fine. I also tested the other 2 sensors;
the one on the inside of the car and the one right above the power
transistor I replaced. Both or should I say all 3 are working fine!
Does anyone have any suggestions? I REALLY need HEAT! Thanks.

 

Fred V.

Maybe you should check the resistance of the sensors right at the circuit
board if you can. There might be a bad connection. Or you count try
replacing the sensor wires at the circuit board with a suitable pot, and see
if the board responds.
Fred

<jryder.10@gmail.com> wrote in message
news:1137184941.052989.58880@g14g2000cwa.googlegroups.com...
> Hey all... after having recently replaced a power transistor to get
> what I thought was a blown blower ($$$$) I thought that my winter heat
> woes were solved, now that the air was back to blowing... But when I
> start it up, the temp display works fine, I can adjust the temp no
> prob. Minutes later I see the temp display go from what I set it to, to
> flashing "08" then the original temp I set, then "08" again! And I hear
> the vent door motors start actuating, but NO heat comes out. Just
> ambient air. I've tried looking everywhere for what this "08" means but
> I cannot find any info.
> The guy that sold my Pop's the car told us it was a temp sensor,
> namely the one in the main vent... so I disassembled the whole dash,
> found it and tested it's resistance with a voltmeter. It increased
> /decreased resistance as it should when I would blow warmer/colder air
> on it. So I know it's working fine. I also tested the other 2 sensors;
> the one on the inside of the car and the one right above the power
> transistor I replaced. Both or should I say all 3 are working fine!
> Does anyone have any suggestions? I REALLY need HEAT! Thanks.
>

Jay

Fred,
Thanks for responding! Hrmm I would have done that orginally
but it was getting cold and dark, that and I didn't think of it at the
time. The problem is getting to the circuit board - there's a HUGE
amont of tubing and wires etc that make 1) finding it a problem and 2)
once found, getting to it... argh, I was hoping that it would have been
as simply as fixing a lose wire or something like that, but geesh, I'm
going to have to dismantle the whole dash, not just the top to get to
the circuit board...argh, well thanks for the advice/suggestion!

BTW - When you said "with a suitable pot" I assume you mean
Potentiometer? And if so, what resistance range? If I recall right the
res on the thermistors was ~4.7K

Thanks,
-J

Fred V.

Hi Jay

Yes, a Potentiometer! Sorry about that. Being in electronics so long
does that. Try a 10 k pot. That should be fine. connect the center and one
end
together and that's one lead, and the free end of the pot is the other lead.
You
might also check if you get any voltage across the sensor leads with them
disconnected. You should probably get some voltage reading of some sort.
No voltage there probably means a
bad connection somewhere or something blown on the circuit board.

Fred

"Jay" <jryder.10@gmail.com> wrote in message
news:1137451273.334271.256170@z14g2000cwz.googlegroups.com...
> Fred,
> Thanks for responding! Hrmm I would have done that orginally
> but it was getting cold and dark, that and I didn't think of it at the
> time. The problem is getting to the circuit board - there's a HUGE
> amont of tubing and wires etc that make 1) finding it a problem and 2)
> once found, getting to it... argh, I was hoping that it would have been
> as simply as fixing a lose wire or something like that, but geesh, I'm
> going to have to dismantle the whole dash, not just the top to get to
> the circuit board...argh, well thanks for the advice/suggestion!
>
> BTW - When you said "with a suitable pot" I assume you mean
> Potentiometer? And if so, what resistance range? If I recall right the
> res on the thermistors was ~4.7K
>
> Thanks,
> -J
>

Jay

Fred,
Hello again, darn... just what I need- a potential blown
circuit board or something that is going to be VERY hard to replace,
and even more hard to find a replacement... Dang this merkur! How
ridiculous, the heat doesn't work b/c of some stupid censor/board... I
could have went american and least the heat would be on the hottest
setting if a censor was messed up Vs NO heat at all... Well thanks
again!

-J