1999 SL 500. Interior switch to operate door locks and switch to open trunk not working. Fuse/Relay?

Do you know anything about automotive electronic's ? The trunk release is controlled by electronic control modules . Having the vehicle check for DTC'S - diagnostic trouble code's should be the first step in the diagnostic procedure . Then reading how it work's !
Factory service repair info.
Rear Compartment Lid Release System Components
• Body control module (BCM)
• Remote control door lock receiver
• Interior rear compartment lid release switch
• Exterior rear compartment lid release switch
• Rear compartment lid release actuator
• Trunk release relay

Rear Compartment Lid Release Operation
The interior rear compartment lid release switch receives a signal from the driver door switch assembly (DDSA). When the interior rear compartment lid release switch is activated, the signal circuit is pulled to ground. The DDSA interprets this and sends a GMLAN serial data message to the body control module (BCM) requesting the rear compartment lid be released. The BCM responds by applying battery voltage to the trunk release relay control circuit which energizes the TRUNK RELES relay. The trunk release relay is supplied with battery voltage at all times. With the relay coil energized, the relay switch contacts close allowing battery voltage to flow to the rear compartment lid release actuator causing the rear compartment lid to release. The rear compartment lid release actuator is permanently grounded at G402.

The trunk release relay is located in the rear fuse box located under the back seat.

Voltage is applied at all times through the TRUNK REL/RFA fuse to the rear compartment lid release switch and the switch side of the rear compartment lid release relay. When the release switch is pressed, the following actions occur:
• The switch closes.
• Voltage is applied to the coil side of the rear compartment lid release relay.
When the transaxle is in PARK or NEUTRAL, the rear compartment lid release relay is grounded through the transaxle range switch. With the coil side of the relay energized, the relay contacts close, applying voltage to the rear compartment lid release motor.
If the vehicle is equipped with remote entry, the switch operation is the same, except when the contacts in the rear compartment lid release relay close, voltage is applied through the normally closed contacts of the remote control door lock receiver. This action occurs in order to apply voltage to the rear compartment lid release motor.

Can you check fuse's , relay ? Both are located in the left insturment panel fuse box . Fuse Block - Left I/P
On the left side of the I/P
you need to open the drivers door to get to it ,on very end of the insturment panel .
Do you know anything about relay's , how they work ? If you pull the relay out of the fuse box an look on the bottom you will see four set's of numbers . 30 & 87 . if you took a piece of wire an jumped were this pins plug into the fuse box the trunk would open . provided there is B+ voltage at pin 30 .
There are videos on youtube showing how to test relays and their circuits .

The rear compartment lid release system consists of the following components:
• Body control module (BCM)
• Folding top cover actuator
• GMLAN serial data link
• Keyless entry transmitter
• Rear compartment lid ajar switch
• Rear compartment lid release actuator
• Rear compartment lid release switch
• Remote control door lock receiver (RCDLR)
• Trunk fuses
• Trunk release relay

Rear Compartment Lid Release System Operation
The rear compartment lid can be released by operating the rear compartment lid release switch or pressing the rear compartment lid release button on the keyless entry transmitter. When the rear compartment lid release switch is operated, the rear compartment lid release switch signal circuit to the body control module (BCM) is switched to ground. The BCM receives the rear compartment lid release switch input and applies ground to the trunk release relay control circuit. This energizes the trunk release relay coil, closing the switch side contacts, allowing battery voltage to be applied to the rear compartment lid release actuator and folding top cover actuator, releasing the buttresses and opening the rear compartment lid. Ground for the rear compartment lid release switch is provided at G300. The rear compartment lid ajar switch, rear compartment lid release actuator, and folding top cover actuator are provided ground at G301. The rear compartment lid will not release until the vehicle speed is zero and in park.

Do you know what DTC'S - diagnostic trouble codes are ?
DTC B3265 01 : Trunk Relay Output Short to Battery
DTC B3265 06 : Trunk Relay Output Short to Ground or Open

Do you know what a relay is an how it works ? TRUNK release relay located in the underhood fuse / relay box.
VEHICLE RELAYS Operation Diagnosis

Hi Jeff,
I was going to say, check fuse/ jump the load side of relay Good post.

It is located on the fuse panel on the Passenger side.
Look for the removable panel that is located below the radio/center bezel on the right side (passenger side). It's not part of the center shifter console, but just forward of it. Remove the panel marked "Fuses"! You will find the Wiper Fuse in this panel along with the fuses for the Radio, Accessory Power Plug/Lighter, Power Door Lock & Window Relays, Fuel Pump Relay, Cruise Control fuse, exc......
Hope this info helps!

i have seen the ignition switch fail not turning on all the options check for power going to the switch

have you checked the fuzes ?

Sounds like one of the door triggers has continuity to earth,(Shorted) Test them all with a multi meter.

Cheers CeeBee

my car did the same u have the replace that control,are take door panel off an unhook it

Hi!

Since you've got a '96 I assume your #15 fuse is 10 amps and for the following components:

Audio System, Courtesy Lights, Door Open Light, Trunk Light, Glove Box Light, Remote Control Central Locking System, Oil Level Sensor, Seat Belt Reminder, Data Link Connector.

Turn ignition to OFF, turn off all interior lighting (by operating the selector inside the car), close all doors, wait about 20 seconds and insert a new fuse. If the fuse is blown immediately upon insertion my guess would be that you have an aftermarket audio system with faulty wiring or maybe something is wrong with you Data Link Connector. If that is not the case the problem might prove a little bit harder to find, and you'll definitely need a wiring diagram. Check this site:
http://www.volvoclub.org.uk/volvo_workshop-850techdocs.shtml

If the fuse is not blown immediately upon insertion: Good, the components affiliated with the fuse can then be grouped by what ignition position they are active at (OFF, 1, 2) and tested individually.

POSITION OFF:
- Door open light, courtesy lights, glove box light, trunk light, remote central locking system.
Make sure the glove box light really is turned off when closing the glove box.
After that it's simply a matter of testing these components one after the other (with the ignition at position OFF) by opening/closing doors, turning on/off trunk light etc, checking the fuse between each component test.
Make sure that the interior lighting is turned off when you test the central locking, or else you might end up faulttracing central locking when the problem was with the interior lighting :)
(Since the interior lights can be set to turn on when the central locking is operated).

POSITION 1:
- Usually the audio system, unless it's an aftermarket system.
If the fuse breaks the second you turn the ignition to position 1 the audio system probably has faulty wiring.

POSITION 2:
If the fuse breaks the second you turn the ignition to position 2 one of these two components is the culprit:
- Seat belt reminder, oil level sensor.
Fasten all seat belts and try again with a new fuse.
If the fuse still breaks the oil level sensor is most likely the culprit.
If the fuse didn't break the seat belt reminder is the culprit. If so you can simply disconnect the seat belt reminder relay, ridding you of both your fuse problem and the annoying seat belt reminder. The relay is located behind the cover over the drivers feet (easily removed, just a couple of torx screws, no breakable interior clips).

The central locking relay and the alarm module are also found there, as well as some other electrical components.

The Data Link Connector is an unlikely culprit, but it's probably best if you unplugged it completely during testing.
If everything turns out ok with it disconnected you can test it at the end. (The Data Link Connector is the OBD II conncetor located by the coin holder, in front of the gearchange).

Good luck!