A/C CLUTCH SOLENOID

Have an 98 Grand Cherokee
The a/c clutch solenoid is staying engaged and running down my battery.
Does any one know if this is a ground seeking or power seeking circuit to
activate the solenoid.
I know a lead comes from the powertrain control module to the a/c compressor
clutch relay, but don't have a diagram or schematic to follow.
Is there a way to test the powertrain control module.

thanks for any help



0|||||||0
Tact is the ability to describe others as they see themselves

Have you tested the connection at the clutch plug for power? I just
can't see, the ignition switch, A/C position switch, and low pressure
switch, all have to be closed at the same time. Unbelievable
coincidence.
God Bless America, ßill O|||||||O
http://www.billhughes.com/

JEEPR wrote:
>
> Have an 98 Grand Cherokee
> The a/c clutch solenoid is staying engaged and running down my battery.
> Does any one know if this is a ground seeking or power seeking circuit to
> activate the solenoid.
> I know a lead comes from the powertrain control module to the a/c compressor
> clutch relay, but don't have a diagram or schematic to follow.
> Is there a way to test the powertrain control module.
>
> thanks for any help
>
> 0|||||||0
> Tact is the ability to describe others as they see themselves

JEEPR did pass the time by typing:
> Have an 98 Grand Cherokee
> The a/c clutch solenoid is staying engaged and running down my battery.
> Does any one know if this is a ground seeking or power seeking circuit to
> activate the solenoid.
> I know a lead comes from the powertrain control module to the a/c compressor
> clutch relay, but don't have a diagram or schematic to follow.
> Is there a way to test the powertrain control module.

Should be the same as my 93ZJ
http://revbeergoggles.com/temp/zj-59.jpg

Pull the relay. If the clutch is still engaged then
it's dead. The clutch can be replaced without having to
disconnect the compressor.

--
DougW

When I pull the relay the solenoid de-energizes.
I'm thinking there is a short somewhere or chaffed wire, supplying maybe a
ground for the solenoid to energize.


0|||||||0
Tact is the ability to describe others as they see themselves


"DougW" > wrote in message
news:JhRfe.8127$Ri4.4760@okepread07...
> JEEPR did pass the time by typing:
> > Have an 98 Grand Cherokee
> > The a/c clutch solenoid is staying engaged and running down my battery.
> > Does any one know if this is a ground seeking or power seeking circuit
to
> > activate the solenoid.
> > I know a lead comes from the powertrain control module to the a/c
compressor
> > clutch relay, but don't have a diagram or schematic to follow.
> > Is there a way to test the powertrain control module.
>
> Should be the same as my 93ZJ
> http://revbeergoggles.com/temp/zj-59.jpg
>
> Pull the relay. If the clutch is still engaged then
> it's dead. The clutch can be replaced without having to
> disconnect the compressor.
>
> --
> DougW
>
>

substituting relays does not rectify it
two wire connector at compressor
need to know if its a case ground on the solenoid


0|||||||0
Tact is the ability to describe others as they see themselves
"JEEPR" > wrote in message
. ..
> When I pull the relay the solenoid de-energizes.
> I'm thinking there is a short somewhere or chaffed wire, supplying maybe a
> ground for the solenoid to energize.
>
>
> 0|||||||0
> Tact is the ability to describe others as they see themselves
>
>
> "DougW" > wrote in message
> news:JhRfe.8127$Ri4.4760@okepread07...
> > JEEPR did pass the time by typing:
> > > Have an 98 Grand Cherokee
> > > The a/c clutch solenoid is staying engaged and running down my
battery.
> > > Does any one know if this is a ground seeking or power seeking circuit
> to
> > > activate the solenoid.
> > > I know a lead comes from the powertrain control module to the a/c
> compressor
> > > clutch relay, but don't have a diagram or schematic to follow.
> > > Is there a way to test the powertrain control module.
> >
> > Should be the same as my 93ZJ
> > http://revbeergoggles.com/temp/zj-59.jpg
> >
> > Pull the relay. If the clutch is still engaged then
> > it's dead. The clutch can be replaced without having to
> > disconnect the compressor.
> >
> > --
> > DougW
> >
> >
>
>

The case provides a continuous ground, the relay provides a switched +12
volts to energize the solenoid. Is your HVAC control on defrost by any
chance?

JEEPR wrote:
> substituting relays does not rectify it
> two wire connector at compressor
> need to know if its a case ground on the solenoid
>
>
> 0|||||||0
> Tact is the ability to describe others as they see themselves
> "JEEPR" > wrote in message
> . ..
>
>>When I pull the relay the solenoid de-energizes.
>>I'm thinking there is a short somewhere or chaffed wire, supplying maybe a
>>ground for the solenoid to energize.
>>
>>
>> 0|||||||0
>>Tact is the ability to describe others as they see themselves
>>
>>
>>"DougW" > wrote in message
>>news:JhRfe.8127$Ri4.4760@okepread07...
>>
>>>JEEPR did pass the time by typing:
>>>
>>>>Have an 98 Grand Cherokee
>>>>The a/c clutch solenoid is staying engaged and running down my
>
> battery.
>
>>>>Does any one know if this is a ground seeking or power seeking circuit
>>
>>to
>>
>>>>activate the solenoid.
>>>>I know a lead comes from the powertrain control module to the a/c
>>
>>compressor
>>
>>>>clutch relay, but don't have a diagram or schematic to follow.
>>>>Is there a way to test the powertrain control module.
>>>
>>>Should be the same as my 93ZJ
>>>http://revbeergoggles.com/temp/zj-59.jpg
>>>
>>>Pull the relay. If the clutch is still engaged then
>>>it's dead. The clutch can be replaced without having to
>>>disconnect the compressor.
>>>
>>>--
>>>DougW
>>>
>>>
>>
>>
>
>

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.cox.net/jerrypb/

Initially it was but it is also doing it in the off selection, why?

--

Matt
0|||||||0
Tact is the ability to describe others as they see themselves
"Jerry Bransford" > wrote in message
news:chTfe.14636$tQ.8380@fed1read06...
> The case provides a continuous ground, the relay provides a switched +12
> volts to energize the solenoid. Is your HVAC control on defrost by any
> chance?
>
> JEEPR wrote:
> > substituting relays does not rectify it
> > two wire connector at compressor
> > need to know if its a case ground on the solenoid
> >
> >
> > 0|||||||0
> > Tact is the ability to describe others as they see themselves
> > "JEEPR" > wrote in message
> > . ..
> >
> >>When I pull the relay the solenoid de-energizes.
> >>I'm thinking there is a short somewhere or chaffed wire, supplying maybe
a
> >>ground for the solenoid to energize.
> >>
> >>
> >> 0|||||||0
> >>Tact is the ability to describe others as they see themselves
> >>
> >>
> >>"DougW" > wrote in message
> >>news:JhRfe.8127$Ri4.4760@okepread07...
> >>
> >>>JEEPR did pass the time by typing:
> >>>
> >>>>Have an 98 Grand Cherokee
> >>>>The a/c clutch solenoid is staying engaged and running down my
> >
> > battery.
> >
> >>>>Does any one know if this is a ground seeking or power seeking circuit
> >>
> >>to
> >>
> >>>>activate the solenoid.
> >>>>I know a lead comes from the powertrain control module to the a/c
> >>
> >>compressor
> >>
> >>>>clutch relay, but don't have a diagram or schematic to follow.
> >>>>Is there a way to test the powertrain control module.
> >>>
> >>>Should be the same as my 93ZJ
> >>>http://revbeergoggles.com/temp/zj-59.jpg
> >>>
> >>>Pull the relay. If the clutch is still engaged then
> >>>it's dead. The clutch can be replaced without having to
> >>>disconnect the compressor.
> >>>
> >>>--
> >>>DougW
> >>>
> >>>
> >>
> >>
> >
> >
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.cox.net/jerrypb/

No idea, sorry. It'd take some troubleshooting with a VOM and the
schematic, that is for sure.

JEEPR wrote:
> Initially it was but it is also doing it in the off selection, why?
>

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.cox.net/jerrypb/

I'm only guessing here, but maybe try pulling the wires off of your ac-
heater controls to check if maybe your switch might be the problem? You
really need a meter to check properly as to what is happening. Even a
cheapo 12V will work fine. The fact that when you pull the relay wires and
the solenoid goes off tells me the problem is farther up the line. Your
low pressure switch will always be closed, unless you have a leak and have
lost refrigerant.

--
Message posted via http://www.carkb.com

JEEPR did pass the time by typing:
> When I pull the relay the solenoid de-energizes.
> I'm thinking there is a short somewhere or chaffed wire, supplying maybe a
> ground for the solenoid to energize.

That is the only thing it could be apart from the AC being on or the
setting being defrost.

The ECU provides a ground (transistor switched) to the relay. A short
anywhere along that wire will energize the relay.

Next step would be to disconnect the battery, and disconnect the harness
from the ecu then ohm out the line. Watch that center bolt for the ecu
plug, it's only there to hold the plug in, not to suck it in. Don't try
to make the plug go in by cranking on the bolt, you will crack the ECU.
That and it only goes hand tight, like a screw into plastic.

In the meanwhile if you don't want it running you can simply yank the
relay. Pulling the high/low pressure switches (either one) will set a
fault code but will also shut off the relay by removing the power feed.
A short in the ECU output to that AC relay won't hurt the ECU.

--
DougW