1999 DODGE RAM light

as the "peak" time, referring to the fact that current flow is allowed
to "peak" (to open the injector).
Once the injector pintle is open, the amp flow is
considerably reduced for the rest of the pulse duration to protect the
injector from overheating. This is okay because very little amperage
is needed to hold the injector open, typically in the area of one amp
or less. Some manufacturers refer to this as the "hold" time, meaning
that just enough current is allowed through the circuit to "hold" the
already-open injector open.
There are a couple methods of reducing the current. The most
common trims back the available voltage for the circuit, similar to
turning down a light at home with a dimmer.
The other method involves repeatedly cycling the circuit ON-
OFF. It does this so fast that the magnetic field never collapses and
the pintle stays open, but the current is still significantly reduced.
See the right side of Fig. 1 for an illustration.
The advantage to the current controlled driver circuit is the
short time period from when the driver transistor goes ON to when the
injector actually opens. This is a function of the speed with which
current flow reaches its peak due to the low circuit resistance. Also,
the injector closes faster when the driver turns OFF because of the
lower holding current.
NOTE: Never apply battery voltage directly across a low resistance
injector. This will cause injector damage from solenoid coil
overheating.
THE TWO WAYS INJECTOR CIRCUITS ARE WIRED
Like other circuits, injector circuits can be wired in one of
two fundamental directions. The first method is to steadily power the
injectors and have the computer driver switch the ground side of the
circuit. Conversely, the injectors can be steadily grounded while the
driver switches the power side of the circuit.
There is no performance benefit to either method. Voltage
controlled and current controlled drivers have been successfully
implemented both ways.
However, 95% percent of the systems are wired so the driver
controls the ground side of the circuit. Only a handful of systems use
the drivers on the power side of the circuit. Some examples of the
latter are the 1970's Cadillac EFI system, early Jeep 4.0 EFI (Renix
system), and Chrysler 1984-87 TBI.
INTERPRETING INJECTOR WAVEFORMS
INTERPRETING A VOLTAGE CONTROLLED PATTERN
NOTE: Voltage controlled drivers are also known as "Saturated
Switch" drivers. They typically require injector circuits
with a total leg resistance of 12 ohms or more.
NOTE: This example is based on a constant power/switched ground
circuit.
* See Fig. 2 for pattern that the following text describes.
Point "A" is where system voltage is supplied to the
injector. A good hot run voltage is usually 13.5 or more volts. This
point, commonly known as open circuit voltage, is critical because the
injector will not get sufficient current saturation if there is a
voltage shortfall. To obtain a good look at this precise point, you

will need to shift your Lab Scope to five volts per division.
You will find that some systems have slight voltage
fluctuations here. This can occur if the injector feed wire is also
used to power up other cycling components, like the ignition coil(s).
Slight voltage fluctuations are normal and are no reason for concern.
Major voltage fluctuations are a different story, however. Major
voltage shifts on the injector feed line will create injector
performance problems. Look for excessive resistance problems in the
feed circuit if you see big shifts and repair as necessary.
Note that circuits with external injector resistors will not
be any different because the resistor does not affect open circuit
voltage.
Point "B" is where the driver completes the circuit to
ground. This point of the waveform should be a clean square point
straight down with no rounded edges. It is during this period that
current saturation of the injector windings is taking place and the
driver is heavily stressed. Weak drivers will distort this vertical
line.
Point "C" represents the voltage drop across the injector
windings. Point "C" should come very close to the ground reference
point, but not quite touch. This is because the driver has a small
amount of inherent resistance. Any significant offset from ground is
an indication of a resistance problem on the ground circuit that needs
repaired. You might miss this fault if you do not use the negative
battery post for your Lab Scope hook-up, so it is HIGHLY recommended
that you use the battery as your hook-up.
The points between "B" and "D" represent the time in
milliseconds that the injector is being energized or held open. This
line at Point "C" should remain flat. Any distortion or upward bend
indicates a ground problem, short problem, or a weak driver. Alert
readers will catch that this is exactly opposite of the current
controlled type drivers (explained in the next section), because they
bend upwards at this point.
How come the difference? Because of the total circuit
resistance. Voltage controlled driver circuits have a high resistance
of 12+ ohms that slows the building of the magnetic field in the
injector. Hence, no counter voltage is built up and the line remains
flat.
On the other hand, the current controlled driver circuit has
low resistance which allows for a rapid magnetic field build-up. This
causes a slight inductive rise (created by the effects of counter
voltage) and hence, the upward bend. You should not see that here with
voltage controlled circuits.
Point "D" represents the electrical condition of the injector
windings. The height of this voltage spike (inductive kick) is
proportional to the number of windings and the current flow through
them. The more current flow and greater number of windings, the more
potential for a greater inductive kick. The opposite is also true. The
less current flow or fewer windings means less inductive kick.
Typically you should see a minimum 35 volts at the top of Point "D".
If you do see approximately 35 volts, it is because a zener
diode is used with the driver to clamp the voltage. Make sure the
beginning top of the spike is squared off, indicating the zener dumped
the remainder of the spike. If it is not squared, that indicates the
spike is not strong enough to make the zener fully dump, meaning the
injector has a weak winding.
If a zener diode is not used in the computer, the spike from
a good injector will be 60 or more volts.
Point "E" brings us to a very interesting section. As you
can see, the voltage dissipates back to supply value after the peak of
the inductive kick. Notice the slight hump? This is actually the
mechanical injector pintle closing. Recall that moving an iron core
through a magnetic field will create a voltage surge. The pintle is

the iron core here.
This pintle hump at Point "E" should occur near the end of
the downward slope, and not afterwards. If it does occur after the
slope has ended and the voltage has stabilized, it is because the
pintle is slightly sticking because of a faulty injector
If you see more than one hump it is because of a distorted
pintle or seat. This faulty condition is known as "pintle float".
It is important to realize that it takes a good digital
storage oscilloscope or analog lab scope to see this pintle hump
clearly. Unfortunately, it cannot always be seen.
Fig. 2: Identifying Voltage Controlled Type Injector Pattern
INTERPRETING A CURRENT CONTROLLED PATTERN
NOTE: Current controlled drivers are also known as "Peak and Hold"

drivers. They typically require injector circuits
with a total leg resistance with less than 12 ohm.
NOTE: This example is based on a constant power/switched ground
circuit.
* See Fig. 3 for pattern that the following text describes.
Point "A" is where system voltage is supplied to the
injector. A good hot run voltage is usually 13.5 or more volts. This
point, commonly known as open circuit voltage, is critical because the
injector will not get sufficient current saturation if there is a
voltage shortfall. To obtain a good look at this precise point, you
will need to shift your Lab Scope to five volts per division.
You will find that some systems have slight voltage
fluctuations here. This could occur if the injector feed wire is also
used to power up other cycling components, like the ignition coil(s).
Slight voltage fluctuations are normal and are no reason for concern.
Major voltage fluctuations are a different story, however. Major
voltage shifts on the injector feed line will create injector
performance problems. Look for excessive resistance problems in the
feed circuit if you see big shifts and repair as necessary.
Point "B" is where the driver completes the circuit to
ground. This point of the waveform should be a clean square point
straight down with no rounded edges. It is during this period that
current saturation of the injector windings is taking place and the
driver is heavily stressed. Weak drivers will distort this vertical
line.
Point "C" represents the voltage drop across the injector
windings. Point "C" should come very close to the ground reference
point, but not quite touch. This is because the driver has a small
amount of inherent resistance. Any significant offset from ground is
an indication of a resistance problem on the ground circuit that needs
repaired. You might miss this fault if you do not use the negative
battery post for your Lab Scope hook-up, so it is HIGHLY recommended
that you use the battery as your hook-up.
Right after Point "C", something interesting happens. Notice
the trace starts a normal upward bend. This slight inductive rise is
created by the effects of counter voltage and is normal. This is
because the low circuit resistance allowed a fast build-up of the
magnetic field, which in turn created the counter voltage.
Point "D" is the start of the current limiting, also known as
the "Hold" time. Before this point, the driver had allowed the current
to free-flow ("Peak") just to get the injector pintle open. By the
time point "D" occurs, the injector pintle has already opened and the
computer has just significantly throttled the current back. It does
this by only allowing a few volts through to maintain the minimum
current required to keep the pintle open.
The height of the voltage spike seen at the top of Point "D"
represents the electrical condition of the injector windings. The
height of this voltage spike (inductive kick) is proportional to the
number of windings and the current flow through them. The more current
flow and greater number of windings, the more potential for a greater
inductive kick. The opposite is also true. The less current flow or
fewer windings means less inductive kick. Typically you should see a
minimum 35 volts.
If you see approximately 35 volts, it is because a zener
diode is used with the driver to clamp the voltage. Make sure the
beginning top of the spike is squared off, indicating the zener dumped
the remainder of the spike. If it is not squared, that indicates the
spike is not strong enough to make the zener fully dump, meaning there
is a problem with a weak injector winding.
If a zener diode is not used in the computer, the spike from

a good injector will be 60 or more volts.
At Point "E", notice that the trace is now just a few volts
below system voltage and the injector is in the current limiting, or
the "Hold" part of the pattern. This line will either remain flat and
stable as shown here, or will cycle up and down rapidly. Both are
normal methods to limit current flow. Any distortion may indicate
shorted windings.
Point "F" is the actual turn-off point of the driver (and
injector). To measure the millisecond on-time of the injector, measure
between points "C" and "F". Note that we used cursors to do it for us;
they are measuring a 2.56 mS on-time.
The top of Point "F" (second inductive kick) is created by
the collapsing magnetic field caused by the final turn-off of the
driver. This spike should be like the spike on top of point "D".
Point "G" shows a slight hump. This is actually the
mechanical injector pintle closing. Recall that moving an iron core
through a magnetic field will create a voltage surge. The pintle is
the iron core here.
This pintle hump at Point "E" should occur near the end of
the downward slope, and not afterwards. If it does occur after the
slope has ended and the voltage has stabilized, it is because the
pintle is slightly sticking. Some older Nissan TBI systems suffered
from this.
If you see more than one hump it is because of a distorted
pintle or seat. This faulty condition is known as "pintle float".
It is important to realize that it takes a good digital
storage oscilloscope or analog lab scope to see this pintle hump
clearly. Unfortunately, it cannot always be seen.
Fig. 3: Identifying Current Controlled Type Injector Pattern

Application Front - In. (mm) Rear - In. (mm\
)
Gas Engine With
14" & 15" Wheels (1) ....... 29.04-29.82
(737.5-757.5) .......... 29.76-30.54\
(756.0-776.0)\
Gas Engine With 15",
16" & 17" Wheels ( 2) ....... 29.27-30.05
(743.5-765.5) ........... 30.0-30.78\
(762.0-782.0)\
CNG & Electric Vehicles ..... 30.46-31.24
(783.5-803.5) ........... 31.2-31.98\
(792.5-812.5)\
( 1) - With tire sizes P205/75R 15 and P215/65R 15.
( 2) - With tire sizes P215/70R 15, P215/65R 16 and 215/65R 17.









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HOIST
CAUTION: On Ram Van/Wagon, ensure there is adequate drive shaft
clearance while raising vehicle. DO NOT raise vehicle by
hoisting or jacking against front lower control arms. If rear
axle, fuel tank, spare tire and liftgate will be removed for
service, place additional weight on rear end of vehicle. This
will prevent tipping as center of gravity changes.
Caravan, Ram Van/Wagon, Town & Country, & Voyager
To raise vehicle on single and twin post type hoists, ensure
hoist pads contact vehicle frame behind front control arm pivots and
inside rear wheels on rear axle housing. Always use hoist adapters.
See Fig. 2 or 5.
Dakota & Ram Pickup
Vehicle may be raised on single or twin post swiveling arm,
or ramp-type drive hoists. If using swiveling arm hoist, ensure
lifting arms, pads or ramps are positioned evenly on frame rails, and
adequate clearance is maintained for transfer case (4WD models) or
skid plate. All hoists must be equipped with adapters to properly
support vehicle. See Fig. 3.
WHEEL ALIGNMENT PROCEDURES
FRONT WHEEL CAMBER & CASTER ADJUSTMENT
CAUTION: DO NOT adjust caster by heating or bending suspension
components. If caster angle is incorrect, replace
component(s) causing incorrect angle.
Caravan, Town & Country, & Voyager
1) Caster is factory preset and cannot be adjusted. Camber is
factory preset, but can be adjusted with a camber service kit. Raise
and support vehicle. While holding lower strut attaching bolts
stationary, loosen attaching nuts. See Fig. 6. Remove upper attaching
nut and bolt. Install camber service kit attaching/adjusting bolt and
nut. While holding bolt stationary, lightly tighten nut. Repeat
procedure for lower attaching nut and bolt.
2) Lower vehicle until vehicle weight is supported by
suspension. Bounce vehicle several times and allow suspension to
settle. Rotate new cam bolt to move top of wheel in or out to
specified camber. See WHEEL ALIGNMENT SPECIFICATIONS table. Tighten
through-bolt nuts to specification. See TORQUE SPECIFICATIONS table.

compartment.
* Inspect power window system ground circuit. See WIRING
DIAGRAMS.
RAM PICKUP
Inspect fuse No. 2 (30-amp) located in Power Distribution
Center (PDC). PDC is located in left side of engine compartment.
* Inspect circuit breaker No. 1 (20-amp) in fuse block. Fuse
block is located under left side of instrument panel.
* Inspect power window system ground circuit. See WIRING
DIAGRAMS.
RAM VAN & RAM WAGON
Inspect circuit breaker No. 20 (20-amp) in junction block.
Junction block is located in left end of instrument panel.
* Inspect fuse No. 12 (40-amp) in Power Distribution Center
(PDC). PDC is located in left side of engine compartment.
* Inspect power window system ground circuit. See WIRING
DIAGRAMS.
COMPONENT TESTS
CIRCUIT BREAKER
Dakota, Durango, Ram Pickup, Ram Van & Ram Wagon
1) Locate circuit breaker for power window system. See
TROUBLE SHOOTING. Pull circuit breaker out slightly, but ensure
circuit breaker terminals still contact terminals in fuse block.
2) Connect voltmeter negative lead to ground. Using voltmeter
positive lead, check both terminals of circuit breaker for battery
voltage. If voltmeter indicates battery voltage at both terminals,
circuit breaker is okay.
3) If voltmeter indicates battery voltage at one terminal
only, replace faulty circuit breaker. If voltmeter indicates no
voltage at either terminal, check for an open or shorted circuit to
circuit breaker. Repair as necessary and recheck system operation.
VENT WINDOW MOTOR
Caravan, Town & Country, & Voyager
1) Remove "D" pillar trim panel. See "D" PILLAR TRIM PANEL
under REMOVAL & INSTALLATION. Disconnect vent window motor connector.
Using jumper wires, apply battery voltage to vent window motor
terminals. Motor should rotate in one direction, moving window open or
closed. If window is in full closed or open position, no movement will
be observed and motor will make a grunting noise.
2) Reverse battery leads. Window should move in opposite
direction. If window does not move or window does not make a grunting
noise, replace vent window motor. If window moved completely open and
closed, motor should be reversed one more time to complete a full
window movement inspection.
3) If motor grunts and window does not move, remove motor
assembly. Check window motor crank for binding. Repair as necessary.
Recheck window operation. If window moves, check power window switch
continuity. See POWER WINDOW SWITCH. Replace switch as necessary. If
window switch is okay, check for open circuit between window motor and
window switch. See WIRING DIAGRAMS. Repair as necessary.

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Switch Position Continuity Between Terminals
Off ................................ 1 & 13; 2 & 13; 3 & 13; 4 & 13;
5 & 13; 6 & 13, 7 & 13; 8 & 13 Up
Driver's Side ............................................. 8 & 11
Passenger's Side ........................................... 4 & 9
Down
Driver's Side (1) ......................................... 6 & 11
Passenger's Side ........................................... 2 & 9
Auto-Down
Driver Side's ( 1) ......................................... 6 & 11
Vent Open
Left ...................................................... 7 & 11
Right ...................................................... 1 & 9
Vent Close
Left ....................................................... 3 & 9
Right ..................................................... 5 & 11
( 1) - Connect battery voltage to terminal No. 9 and ground to terminal
No. 13 before testing.









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DRIVER'S WINDOW SWITCH CONTINUITY (DAKOTA & RAM PICKUP)








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Switch Position Continuity Between Terminals
Off ..................................... 1 & 3; 2 & 3; 3 & 4; 3 & 6
Up
Left ................................................ 3 & 4; 5 & 6
Right ............................................... 1 & 5; 2 & 3
Down
Left ................................................ 3 & 6; 4 & 5
Right ............................................... 1 & 3; 2 & 5
Light ........................................................ 3 & 5









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DRIVER'S WINDOW SWITCH CONTINUITY (DURANGO)








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Switch Position Continuity Between Terminals
Off ................................... 2 & 5; 3 & 5; 5 & 6; 5 & 11;
5 & 12; 5 & 13; 5 & 14
Up
Left Front ( 1) ............................................. 4 & 6
Right Front ......................................... 2 & 5; 3 & 4
Left Rear ......................................... 4 & 14; 5 & 13
Right Rear ........................................ 4 & 12; 5 & 11
Down
Left Front ( 1) ............................................. 5 & 6
Right Front ......................................... 2 & 4; 3 & 5
Left Rear ......................................... 4 & 13; 5 & 14
Right Rear ........................................ 4 & 11; 5 & 12
Auto-Down
Left Front ................................................... ( 1)
Power Window Lock-Out ........................................ 4 & 7
( 1) - Vehicles equipped with Auto Down feature have electronic
components in switch to actuate Auto Down. To test,
check switch continuity, reconnect switch, turn ignition on and
test feature. If Auto Down does not work, replace switch.









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