Buss class G Fuss,type SC, Amp 25, time-delay

instrument panel fuse box - RDO/AMP fuse 25 amp .

Fuse Block - I/P
Right side of the I/P, behind the access panel

Open the passenger door , at the end of the instrument panel .

This may be a bad rear integrated control module. or connection or wiring to it.
REAR INTEGRATION MODULE (RIM)
The CTD system is an internal function of the rear integration module (RIM) which utilizes class 2 serial data and various switch input information to perform CTD functions. When the RIM detects an unauthorized entry, the RIM sends a message via the serial data circuit to the DIM to activate the horns and exterior lamps. The RIM has 5 basic modes. Disarmed, standby, delayed, armed, and alarm for operating the CTD system. The 5 modes transition from one step to the next in the following order:

When in the disarmed mode, ignition is OFF and any door is open the RIM commands the instrument cluster to flash the SECURITY indicator via the class 2 serial data circuit. The RIM has the CTD system in a disarmed mode until the following conditions are detected:

Ignition key turned to the OFF position
Any door open
Doors locked by either the power door lock switch or the LOCK button on the keyless entry transmitter

The RIM enters the standby mode when the above conditions are detected. In standby mode the RIM commands the instrument cluster to illuminate the SECURITY indicator via the class 2 serial data circuit. If all the doors are closed and the LOCK button on the keyless entry transmitter is used, the RIM enters the delayed mode.
When the last door is closed, the RIM enters the delayed mode for 30 seconds . In delayed mode the RIM commands the instrument cluster to illuminate the SECURITY indicator on steady via the class 2 serial data circuit.
After 30 seconds , the RIM enters the armed mode. In armed mode the RIM commands the instrument cluster to turn off the SECURITY indicator via the class 2 serial data circuit. Any forced entry activates the alarm mode.

IMPORTANT: The CTD system can be armed with the windows or sunroof open.

look for a damaged wiring to the accessories , bad relay for the accessories or problem switch

Having a factory or professional type scan tool hooked up checking DTC'S - diagnostic trouble codes in all the modules on the vehicle . Insturment cluster , PCM , BCM ,ABS , SRS etc.... Should be the first step in the diagnostic procedure.. Could have a serial data network problem . Do you know what a serial data buss is ? In the case of your vehicle it is GM class 2 data buss . Anytime a bunch of thing's electrical wierd out , suspect the buss.Buick , chevy , cadillac , olds , pontiac all used this .
Buick Class 2 Operation Diagnosis 1998

replace it with a bigger fuss type if its 20 use a 25 or 30 until this issue stops

Have you had all the moduels check for code's ? Not autozone or anywhere else like that . Need professional type . Could have a GMLAN serial data network problem . All the control modules on the vehicle , PCM/ECM , BCM , instrument cluster , radio , air bag's , ABS , electric power steering etc... all share information on the data network . GMLAN is GM'S version of C.A.N. - controller area network . How to Diagnose Controller Area Network CAN Checking for communication problem codes is the first thing to do with problems like you are having . Have you taken it to a Chevy dealer ? This does sound like a data network problem .

The communication among control modules is performed through the GMLAN high speed serial data circuit and the GMLAN low speed serial data circuit. The modules that need real time communication are attached to the high speed GMLAN network. The body control module (BCM) is the gateway between the networks. The purpose of the gateway is to translate serial data messages between the GMLAN high speed buss and the GMLAN low speed buss. The gateway will interact with each network according to that network's transmission protocol. Refer to Body Control System Description and Operation for more information about the gateway.
The powertrain control module (PCM) on this vehicle, uses a class 2 serial data buss. The class 2 buss is only used for diagnostics and the service programming system (SPS). During normal vehicle operations, there is no communications over the class 2 serial data buss. Normal vehicle operational messaging for the PCM is sent over the PCMs GMLAN high speed serial data buss.


Could be a simple fix , i see them all the time . Lose ground wire for one of the modules . That includes the instrument cluster , it also has a microprocessor inside an can set DTC'S -diagnostic trouble codes . Finding a U code in one of the modules would shorten diagnostic time .

The fuse box is located on the leftside under the dash, i will see if i can send a diagram to help you locate it . the blower fuse is # 25 and the cig lighter is 33, heres a diagram of the fuse setup, hope this helps.

Sorry for the long delay. Due to the bad economy, Questions have risen 50% in the last 4-months.
1989 Mercedes-Benz 300-Class ALL (CE, E, SE, SEL & TE)
Firing Order:
1-5-3-6-2-4
Cylinders:
6
5
4
3
2
1

Let me know if this helped, or if you have additional information or questions. Feel free to contact me at FixYa.com

On the Fuse Block, Cavity 25, 30 AMP c/BRK

Review the ZJ-Secc-8W-Wiring-Diagrams: http://www.scribd.com/doc/4790640/93ZJ-Secc-8W-Wiring-Diagrams

Hope helped (remember rated this). Good luck.