Since this group seems to be the keeper of all(nearly) knowledge, I
thought I would start here....

I have a 1996 Blazer that the AC request signal quit on. The clutch
still works, I apply 12V to the pins on the clutch and it kicks right
in. For some reason, the AC req is not getting set.

Anyone have any ideas? I have checked for loose connections on
everything, but have not found anything obvious.

I dont' have a code scanner to check and see what it thinks is wrong.
I know what my options are(evap temp sensor, blower speed sensor, low
refrigerent sensor, etc) but dont' have a good way of figuring it out
until I get a chance to borrow a code scanner.

Thanks

JW

jw wrote:

Since this group seems to be the keeper of all(nearly) knowledge, I
thought I would start here....

I have a 1996 Blazer that the AC request signal quit on. The clutch
still works, I apply 12V to the pins on the clutch and it kicks right
in. For some reason, the AC req is not getting set.

Anyone have any ideas? I have checked for loose connections on
everything, but have not found anything obvious.

I dont' have a code scanner to check and see what it thinks is wrong.
I know what my options are(evap temp sensor, blower speed sensor, low
refrigerent sensor, etc) but dont' have a good way of figuring it out
until I get a chance to borrow a code scanner.

I doubt your code scanner will give you what you need. You need a service manual
which should have the diagnostic tree for nonoperative AC.

If your AC hardware is all OK it would seem it has to be your dash switches, a
fuse, or wiring.

I did this recently for my cruise control and found that it was the cruise
control module that was broken. I didn't have a service manual so I bought one
off ebay, a duplicate CD version, I didn't care, works fine. Handy to have. Your
vehicle is the same year as mine '96, about time you had a service manual anyway.

GWE

When freon is low the system won't let the cluch engage. Preventing
damage, bypass the presure switch
on the dryer if the cluch engages its low freon.

Just a guess - a thermostat in the air system some where is stuck open or the line is open.

But I don't do that for a living - but remember where my book is - Used book store.
Look one of those up - they have Chilton books there for sale cheap - and have many many years.

Martin
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder



jw wrote:
Since this group seems to be the keeper of all(nearly) knowledge, I
thought I would start here....

I have a 1996 Blazer that the AC request signal quit on. The clutch
still works, I apply 12V to the pins on the clutch and it kicks right
in. For some reason, the AC req is not getting set.

Anyone have any ideas? I have checked for loose connections on
everything, but have not found anything obvious.

I dont' have a code scanner to check and see what it thinks is wrong.
I know what my options are(evap temp sensor, blower speed sensor, low
refrigerent sensor, etc) but dont' have a good way of figuring it out
until I get a chance to borrow a code scanner.

Thanks

JW


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jw writes:

Anyone have any ideas?

First thing is check the low-side pressure. You probably have a
refrigerant leak and the pressure cutouts are not letting the system
engage. You can get a cheap gage for about $20.

I have typically bought the "real" service manual for all of my
vehicles, but never got around to it on this one. For the most part,
it has been solid. It's accumulated 140k and nothing strange has
happened to it. Replaced a bad alternator(typical of GM), and
basics(brakes, filters, etc). At this point I figure it is down to
about a year of serviceable life left(I drive a lot so that will be
around 170k).

Maybe I will check and see if the library has a Chilton's. They are
miserable manuals, but they might be enough to get me by.

I know someone with a set of gauges, I will see if I can borrow them
and check the freon levels. Maybe it just needs a boost, but it had
been working pretty good up till then.

JW

Can I just jumper it? I thought so, but wasn't entirely sure so didn't
want to try it until I looked at a schematic.

JW