My liftgate wont go up on my 1999 Isuzu Box truck. Where is the manual switch for liftgate?

Does it have a power lift gate ? Do you know anything about automotive electrical systems ? How to use a wiring diagram along with a digital volt ohmmeter to test electrical circuits . ?
Power Liftgate
The power liftgate feature will allow the customer to automatically open or close the liftgate by activating the interior open/close switch, the remote keyless entry transmitter, or by manually initiating liftgate movement. The power liftgate uses a power cinch system to latch the liftgate.
The power liftgate system consists of:

• Power liftgate control switch (located in the overhead console)
• Power liftgate motors (located in the rear headliner area)
• Optical sensor and power liftgate encoder wheel (located in the left power liftgate motor assembly)
• Pinch strip switches (located on the body by the liftgate)
• Home position switch (located on the cinch actuator)
• Forkbolt switch (located on the cinching latch assembly)
• Detent switch (located on the cinching latch assembly)
• Liftgate close chime module (located in a unit external from the power liftgate module)

The forkbolt and detent switch are located on the cinch latch assembly and the home position switch is located on the cinch actuator assembly. For information on removal of the latch or cinch actuator assembly, refer to Section 501-14 .
The power liftgate may not operate under the following conditions:

• a low voltage or dead battery.
• a disconnected battery.
• a power liftgate that has been left open for more than six hours.
• a power liftgate that has been manually closed and left ajar.

If any of these conditions has occurred, the power liftgate must be reset before performing any pinpoint tests. For additional information, refer to Power Liftgate Initialization .

Power Liftgate Initialization NOTE: If the power liftgate system is turned OFF in the message center, the system cannot be activated with any switches or with the liftgate handle. The system will need to be turned ON for any power operation to occur.
NOTE: The power liftgate may not operate under the following conditions:

• a low voltage or dead battery.
• a disconnected battery
• a power liftgate that has been left open for more than six hours.
• a power liftgate that has been manually closed and left ajar.

If any of these conditions has occurred, the power liftgate must be reset.

1. Manually close and fully latch the power liftgate.

1. NOTE: If the power liftgate does not open during this step, refer to the symptom chart to diagnose the power liftgate for no operation. Power open the power liftgate by using the keyfob or overhead console switch.

1. Once the power liftgate is fully open, close the power liftgate by using the keyfob or overhead console switch.
2. your best bet mite be to have a qualified repair shop check it out .

Hatch or liftgate ?
Liftgate Release
The liftgate release switch operates the liftgate latch electronically. When the switch is pressed, the SJB processes the input and releases the liftgate latch.
The doors must be unlocked electronically in order for the SJB to release the liftgate latch. When this condition is met and the SJB receives the input from the liftgate release switch, the SJB provides power to the latch release motor.

SJB - smart junction box , fords BCM - body control module .
Your best bet , take it to the dealer .
B2666 Liftgate Release Switch Circuit Failure Go To Pinpoint Test I . B273A Liftgate Release Output Circuit Shorted to Ground Go To Pinpoint Test I . B273B Liftgate Release Output Circuit Open or Shorted to Battery Voltage Go To Pinpoint Test I .

You have to pull the inside door panel off an check it out , only way !

• The lift gate latch release is inoperative/does not operate correctly

• Circuitry
• Liftgate release switch (integral to the liftgate release handle)
• Liftgate release motor (integral to the liftgate latch)
• Power liftgate module
• SJB

• Go To Pinpoint Test F .

Normal Operation The smart junction box (SJB) does not release the liftgate unless the doors have been unlocked electronically or the request is initiated from a remote keyless entry (RKE) transmitter.
The SJB sends a voltage signal to the liftgate release switch (part of the liftgate release handle) through circuit CPL45 (BN). When the switch is activated (the handle is pulled), the signal is routed to ground through circuit GD150 (BK/WH). When the SJB detects a request from the liftgate release switch, the SJB provides voltage through circuit CPL10 (BN/BU) to the liftgate latch release motor (integral to the liftgate latch) (vehicles with a manual liftgate) or the power liftgate module (vehicles equipped with a power liftgate). For vehicles with a manual liftgate, ground for the liftgate latch is provided through circuit GD150 (BK/WH).
DTC B2666 - is an on-demand DTC that sets when the SJB detects a short to ground from the liftgate release switch input circuit.
DTC B273A - is an on-demand DTC that sets when the SJB detects a short to ground from the liftgate latch release output circuit.
DTC B273B - is an on-demand DTC that sets when the SJB detects an open or short to voltage from the liftgate latch release output circuit.

Possible Causes
• Circuit CPL45 (BN) open or short to ground
• Circuit CPL10 (GN/WH) open, short to ground or voltage
• Circuit GD150 (BK/WH) open
• Liftgate release switch (integral to the liftgate release handle)
• Liftgate release motor (integral to the liftgate latch)
• Power liftgate module
• SJB

Your best bet is to take it to the dealer !

The liftgate can be opened by operating the switch on the instrument panel. Battery voltage is supplied to the liftgate actuator through the body control module (BCM). The BCM will pulse the liftgate actuator when a release input is received through the key fob, or the instrument panel switch.
Not sure what your talking about . There is no sensor. there is a relay in the I/P fuse box LIFTGATE PCB relay . an a lift gate actuator motor inside the door . An there is a door ajar switch ,which is part of the latch mechanism. Do you have light lit on the instrument cluster - a picture of a little car with a door open , an maybe a chime sounding ?

Not

First does it work manually? If it does than it must be checked electrically within the rear hatch behind the panel. You cold jump the switch but be careful not to short out the body control module.

Try looking at the fuse box under the rear seat. There is a fuse just for the liftgate, location will either be in your owners manual or on the bottom of the fuse box top.

Also, another common failure is the wiring harness at the top of the door. Remove the rubber grommet and take a look at the wiring right there, look for chaffing and repair if needed.

The last thing to look at IF the other 2 check out would possibly be a new liftgate module.

Did you find out a solution to your problem? I have a 1996 trooper that is showing most of the same symptoms that you have. I'm curious as to your fix. Was it simply a bad ground?

have seen problems with the liftgate handle switches and wiring..under trim on liftgate..remove screws under trim and check wiring to switch..switch is available from dealer

http://www.extendedgmwarranty.com/owners-manual/chevrolet/1999-Chevrolet-Suburban.pdf this link takes you to an online manual for your vehicle, after clicking on this link go to the "service and appearance care" and then "electrical systems" this shows you a layout of fuse box

Please rate my help, thanks

Cable must of disconnected need to take door cover off and reconnect...