Lon

There should be a +12 feed right from the battery to the solenoid
whether or not the key is on.

This is the huge wire that carries way too much current to be switched
by the key, the starter relay etc. The solenoid is what switches this
high current 12 volts to the starter when you turn the key to start...it
is just a very large high current relay.

Your ignition switch has two circuits that control the starter.

The ground side of the ignition switch signal is routed through the
park/neutral switch on an automatic transmission. If that circuit is
open your starter relay will not close.

The hot side of the ignition switch signal heads for the small starter
relay. The starter relay will send +12 to the starter solenoid when you
turn the switch to start...if none of the interlocks prevent this.

Your solenoid always has +12 on it while the battery is connected. The
small +12 wire from the starter relay is used to switch the solenoid so
the high current 12 v goes to the starter. If you have a big sears or
similar screwdriver, you can turn on your solenoid by jumpering the big
red wire to the output to the starter. If that turns over the engine,
then one of the interlocks, the ignition switch, the start relay etc. is
the culprit. If you cannot turn the engine over with a direct jump
across the solenoid, you have a bad cable, which includes the ground
side of your battery.

Common mistake in diagnosing is to check voltages from the connector at
the battery... need to use the posts themselves.

Your problem sounds somewhat like an interlock, which can be a real bear
to isolate unless you have friends and a long diagnostic jumper wire or
take a spare starter relay apart and jump across it.

However, check the big cabling first.

With someone helping by turning the starter on, measure the voltages to
ground and to the starter solenoid large wire.

From the ground post on the battery to the engine and then again to the
body, you should see well under 0.2 volts with the switch to start.

Then check from the positive post to the solenoid, again with switch to
start, you should see well under 0.2 volts.

Any point where you see more than 0.1 volt is a big red flag of a bad
cable or connection.


D proclaimed:

> All,
> I did a voltage check across the two connections on the strarter solenoid
> and have 12.5vdc with the key off. By looking in the manual, that should not
> have voltage until the key is turned to the start position. Is that right? I
> thought the negative side got it's ground through the engine starter relay
> in the power distribution center.
> I failed to clarify in my earlier post that I get no action from the starter
> motor.
> Thanks
> D
>
> "D" <none@none.com> wrote in message
> news:46a14eb6$0$30603$4c368faf@roadrunner.com...
>
>>Hi All,
>>I have a 2002 Grand Cherokee, 4.7 V-8. Went to start it and only a small
>>click from under the hood. Jumping the battery was no joy.
>>First thing to check before I look for my manual?
>>Thanks
>>D
>
>
>

Mike Romain

Lon wrote:

>
> Your problem sounds somewhat like an interlock,

Do you think he would get a full volt drop at the battery on 'start'
without the starter pulling power? He does say he hears a click, but
that might not be the starter solenoid...

Good point about the interlocks though, trying to start it in neutral
would be worth a try.


Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Mike Romain

Lon wrote:

>
> Your problem sounds somewhat like an interlock,

Do you think he would get a full volt drop at the battery on 'start'
without the starter pulling power? He does say he hears a click, but
that might not be the starter solenoid...

Good point about the interlocks though, trying to start it in neutral
would be worth a try.


Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Mike Romain

Lon wrote:

>
> Your problem sounds somewhat like an interlock,

Do you think he would get a full volt drop at the battery on 'start'
without the starter pulling power? He does say he hears a click, but
that might not be the starter solenoid...

Good point about the interlocks though, trying to start it in neutral
would be worth a try.


Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Mike Romain

Lon wrote:

>
> Your problem sounds somewhat like an interlock,

Do you think he would get a full volt drop at the battery on 'start'
without the starter pulling power? He does say he hears a click, but
that might not be the starter solenoid...

Good point about the interlocks though, trying to start it in neutral
would be worth a try.


Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

D

You guys are all great! I printed this out for future use Lon. Very good
info.
Problem solved, for now anyway. I put a deep charge on the battery and got
a start. I redid every connection on the solenoid and prepped the cables for
a new battery.
Charging circuit seems to check out okay. With a 'guarded' thank you, I'll
see how it goes. I might stop into Autozone just to confirm my readings that
the charging system is working up to par.
Thank you all again for your prompt and very informative help.
D

"Lon" <lon.stowell@comcast.net> wrote in message
news:GuydnaR4G9-osD_bnZ2dnUVZ_rWtnZ2d@comcast.com...
> There should be a +12 feed right from the battery to the solenoid
> whether or not the key is on.
>
> This is the huge wire that carries way too much current to be switched
> by the key, the starter relay etc. The solenoid is what switches this
> high current 12 volts to the starter when you turn the key to start...it
> is just a very large high current relay.
>
> Your ignition switch has two circuits that control the starter.
>
> The ground side of the ignition switch signal is routed through the
> park/neutral switch on an automatic transmission. If that circuit is
> open your starter relay will not close.
>
> The hot side of the ignition switch signal heads for the small starter
> relay. The starter relay will send +12 to the starter solenoid when you
> turn the switch to start...if none of the interlocks prevent this.
>
> Your solenoid always has +12 on it while the battery is connected. The
> small +12 wire from the starter relay is used to switch the solenoid so
> the high current 12 v goes to the starter. If you have a big sears or
> similar screwdriver, you can turn on your solenoid by jumpering the big
> red wire to the output to the starter. If that turns over the engine,
> then one of the interlocks, the ignition switch, the start relay etc. is
> the culprit. If you cannot turn the engine over with a direct jump
> across the solenoid, you have a bad cable, which includes the ground
> side of your battery.
>
> Common mistake in diagnosing is to check voltages from the connector at
> the battery... need to use the posts themselves.
>
> Your problem sounds somewhat like an interlock, which can be a real bear
> to isolate unless you have friends and a long diagnostic jumper wire or
> take a spare starter relay apart and jump across it.
>
> However, check the big cabling first.
>
> With someone helping by turning the starter on, measure the voltages to
> ground and to the starter solenoid large wire.
>
> From the ground post on the battery to the engine and then again to the
> body, you should see well under 0.2 volts with the switch to start.
>
> Then check from the positive post to the solenoid, again with switch to
> start, you should see well under 0.2 volts.
>
> Any point where you see more than 0.1 volt is a big red flag of a bad
> cable or connection.
>
>
> D proclaimed:
>
> > All,
> > I did a voltage check across the two connections on the strarter
solenoid
> > and have 12.5vdc with the key off. By looking in the manual, that should
not
> > have voltage until the key is turned to the start position. Is that
right? I
> > thought the negative side got it's ground through the engine starter
relay
> > in the power distribution center.
> > I failed to clarify in my earlier post that I get no action from the
starter
> > motor.
> > Thanks
> > D
> >
> > "D" <none@none.com> wrote in message
> > news:46a14eb6$0$30603$4c368faf@roadrunner.com...
> >
> >>Hi All,
> >>I have a 2002 Grand Cherokee, 4.7 V-8. Went to start it and only a small
> >>click from under the hood. Jumping the battery was no joy.
> >>First thing to check before I look for my manual?
> >>Thanks
> >>D
> >
> >
> >

D

You guys are all great! I printed this out for future use Lon. Very good
info.
Problem solved, for now anyway. I put a deep charge on the battery and got
a start. I redid every connection on the solenoid and prepped the cables for
a new battery.
Charging circuit seems to check out okay. With a 'guarded' thank you, I'll
see how it goes. I might stop into Autozone just to confirm my readings that
the charging system is working up to par.
Thank you all again for your prompt and very informative help.
D

"Lon" <lon.stowell@comcast.net> wrote in message
news:GuydnaR4G9-osD_bnZ2dnUVZ_rWtnZ2d@comcast.com...
> There should be a +12 feed right from the battery to the solenoid
> whether or not the key is on.
>
> This is the huge wire that carries way too much current to be switched
> by the key, the starter relay etc. The solenoid is what switches this
> high current 12 volts to the starter when you turn the key to start...it
> is just a very large high current relay.
>
> Your ignition switch has two circuits that control the starter.
>
> The ground side of the ignition switch signal is routed through the
> park/neutral switch on an automatic transmission. If that circuit is
> open your starter relay will not close.
>
> The hot side of the ignition switch signal heads for the small starter
> relay. The starter relay will send +12 to the starter solenoid when you
> turn the switch to start...if none of the interlocks prevent this.
>
> Your solenoid always has +12 on it while the battery is connected. The
> small +12 wire from the starter relay is used to switch the solenoid so
> the high current 12 v goes to the starter. If you have a big sears or
> similar screwdriver, you can turn on your solenoid by jumpering the big
> red wire to the output to the starter. If that turns over the engine,
> then one of the interlocks, the ignition switch, the start relay etc. is
> the culprit. If you cannot turn the engine over with a direct jump
> across the solenoid, you have a bad cable, which includes the ground
> side of your battery.
>
> Common mistake in diagnosing is to check voltages from the connector at
> the battery... need to use the posts themselves.
>
> Your problem sounds somewhat like an interlock, which can be a real bear
> to isolate unless you have friends and a long diagnostic jumper wire or
> take a spare starter relay apart and jump across it.
>
> However, check the big cabling first.
>
> With someone helping by turning the starter on, measure the voltages to
> ground and to the starter solenoid large wire.
>
> From the ground post on the battery to the engine and then again to the
> body, you should see well under 0.2 volts with the switch to start.
>
> Then check from the positive post to the solenoid, again with switch to
> start, you should see well under 0.2 volts.
>
> Any point where you see more than 0.1 volt is a big red flag of a bad
> cable or connection.
>
>
> D proclaimed:
>
> > All,
> > I did a voltage check across the two connections on the strarter
solenoid
> > and have 12.5vdc with the key off. By looking in the manual, that should
not
> > have voltage until the key is turned to the start position. Is that
right? I
> > thought the negative side got it's ground through the engine starter
relay
> > in the power distribution center.
> > I failed to clarify in my earlier post that I get no action from the
starter
> > motor.
> > Thanks
> > D
> >
> > "D" <none@none.com> wrote in message
> > news:46a14eb6$0$30603$4c368faf@roadrunner.com...
> >
> >>Hi All,
> >>I have a 2002 Grand Cherokee, 4.7 V-8. Went to start it and only a small
> >>click from under the hood. Jumping the battery was no joy.
> >>First thing to check before I look for my manual?
> >>Thanks
> >>D
> >
> >
> >

D

You guys are all great! I printed this out for future use Lon. Very good
info.
Problem solved, for now anyway. I put a deep charge on the battery and got
a start. I redid every connection on the solenoid and prepped the cables for
a new battery.
Charging circuit seems to check out okay. With a 'guarded' thank you, I'll
see how it goes. I might stop into Autozone just to confirm my readings that
the charging system is working up to par.
Thank you all again for your prompt and very informative help.
D

"Lon" <lon.stowell@comcast.net> wrote in message
news:GuydnaR4G9-osD_bnZ2dnUVZ_rWtnZ2d@comcast.com...
> There should be a +12 feed right from the battery to the solenoid
> whether or not the key is on.
>
> This is the huge wire that carries way too much current to be switched
> by the key, the starter relay etc. The solenoid is what switches this
> high current 12 volts to the starter when you turn the key to start...it
> is just a very large high current relay.
>
> Your ignition switch has two circuits that control the starter.
>
> The ground side of the ignition switch signal is routed through the
> park/neutral switch on an automatic transmission. If that circuit is
> open your starter relay will not close.
>
> The hot side of the ignition switch signal heads for the small starter
> relay. The starter relay will send +12 to the starter solenoid when you
> turn the switch to start...if none of the interlocks prevent this.
>
> Your solenoid always has +12 on it while the battery is connected. The
> small +12 wire from the starter relay is used to switch the solenoid so
> the high current 12 v goes to the starter. If you have a big sears or
> similar screwdriver, you can turn on your solenoid by jumpering the big
> red wire to the output to the starter. If that turns over the engine,
> then one of the interlocks, the ignition switch, the start relay etc. is
> the culprit. If you cannot turn the engine over with a direct jump
> across the solenoid, you have a bad cable, which includes the ground
> side of your battery.
>
> Common mistake in diagnosing is to check voltages from the connector at
> the battery... need to use the posts themselves.
>
> Your problem sounds somewhat like an interlock, which can be a real bear
> to isolate unless you have friends and a long diagnostic jumper wire or
> take a spare starter relay apart and jump across it.
>
> However, check the big cabling first.
>
> With someone helping by turning the starter on, measure the voltages to
> ground and to the starter solenoid large wire.
>
> From the ground post on the battery to the engine and then again to the
> body, you should see well under 0.2 volts with the switch to start.
>
> Then check from the positive post to the solenoid, again with switch to
> start, you should see well under 0.2 volts.
>
> Any point where you see more than 0.1 volt is a big red flag of a bad
> cable or connection.
>
>
> D proclaimed:
>
> > All,
> > I did a voltage check across the two connections on the strarter
solenoid
> > and have 12.5vdc with the key off. By looking in the manual, that should
not
> > have voltage until the key is turned to the start position. Is that
right? I
> > thought the negative side got it's ground through the engine starter
relay
> > in the power distribution center.
> > I failed to clarify in my earlier post that I get no action from the
starter
> > motor.
> > Thanks
> > D
> >
> > "D" <none@none.com> wrote in message
> > news:46a14eb6$0$30603$4c368faf@roadrunner.com...
> >
> >>Hi All,
> >>I have a 2002 Grand Cherokee, 4.7 V-8. Went to start it and only a small
> >>click from under the hood. Jumping the battery was no joy.
> >>First thing to check before I look for my manual?
> >>Thanks
> >>D
> >
> >
> >

D

You guys are all great! I printed this out for future use Lon. Very good
info.
Problem solved, for now anyway. I put a deep charge on the battery and got
a start. I redid every connection on the solenoid and prepped the cables for
a new battery.
Charging circuit seems to check out okay. With a 'guarded' thank you, I'll
see how it goes. I might stop into Autozone just to confirm my readings that
the charging system is working up to par.
Thank you all again for your prompt and very informative help.
D

"Lon" <lon.stowell@comcast.net> wrote in message
news:GuydnaR4G9-osD_bnZ2dnUVZ_rWtnZ2d@comcast.com...
> There should be a +12 feed right from the battery to the solenoid
> whether or not the key is on.
>
> This is the huge wire that carries way too much current to be switched
> by the key, the starter relay etc. The solenoid is what switches this
> high current 12 volts to the starter when you turn the key to start...it
> is just a very large high current relay.
>
> Your ignition switch has two circuits that control the starter.
>
> The ground side of the ignition switch signal is routed through the
> park/neutral switch on an automatic transmission. If that circuit is
> open your starter relay will not close.
>
> The hot side of the ignition switch signal heads for the small starter
> relay. The starter relay will send +12 to the starter solenoid when you
> turn the switch to start...if none of the interlocks prevent this.
>
> Your solenoid always has +12 on it while the battery is connected. The
> small +12 wire from the starter relay is used to switch the solenoid so
> the high current 12 v goes to the starter. If you have a big sears or
> similar screwdriver, you can turn on your solenoid by jumpering the big
> red wire to the output to the starter. If that turns over the engine,
> then one of the interlocks, the ignition switch, the start relay etc. is
> the culprit. If you cannot turn the engine over with a direct jump
> across the solenoid, you have a bad cable, which includes the ground
> side of your battery.
>
> Common mistake in diagnosing is to check voltages from the connector at
> the battery... need to use the posts themselves.
>
> Your problem sounds somewhat like an interlock, which can be a real bear
> to isolate unless you have friends and a long diagnostic jumper wire or
> take a spare starter relay apart and jump across it.
>
> However, check the big cabling first.
>
> With someone helping by turning the starter on, measure the voltages to
> ground and to the starter solenoid large wire.
>
> From the ground post on the battery to the engine and then again to the
> body, you should see well under 0.2 volts with the switch to start.
>
> Then check from the positive post to the solenoid, again with switch to
> start, you should see well under 0.2 volts.
>
> Any point where you see more than 0.1 volt is a big red flag of a bad
> cable or connection.
>
>
> D proclaimed:
>
> > All,
> > I did a voltage check across the two connections on the strarter
solenoid
> > and have 12.5vdc with the key off. By looking in the manual, that should
not
> > have voltage until the key is turned to the start position. Is that
right? I
> > thought the negative side got it's ground through the engine starter
relay
> > in the power distribution center.
> > I failed to clarify in my earlier post that I get no action from the
starter
> > motor.
> > Thanks
> > D
> >
> > "D" <none@none.com> wrote in message
> > news:46a14eb6$0$30603$4c368faf@roadrunner.com...
> >
> >>Hi All,
> >>I have a 2002 Grand Cherokee, 4.7 V-8. Went to start it and only a small
> >>click from under the hood. Jumping the battery was no joy.
> >>First thing to check before I look for my manual?
> >>Thanks
> >>D
> >
> >
> >

Lon

Mike Romain proclaimed:

> Lon wrote:
>
>>
>> Your problem sounds somewhat like an interlock,
>
>
> Do you think he would get a full volt drop at the battery on 'start'
> without the starter pulling power? He does say he hears a click, but
> that might not be the starter solenoid...

Yeah, that volt drop is odd. However, he also said the lights don't
dim, which is hard to reconcile with the full volt of drop.

If the click is loud, suspect would be simple bad battery that won't
pass a load test, cables, or possibly the ground on the '02 carries on
the grand old traditions.

If the click is quieter, could be the start relay... in which case the
interlocks are off the suspect list.
>
> Good point about the interlocks though, trying to start it in neutral
> would be worth a try.

The switch could be bad.

I'd be more likely to use a Sears screwdriver at the solenoid.