From RonStygar_at_aol.com Wed Jan 27 00:25:17 1999
From: RonStygar_at_aol.com
Date: Wed, 27 Jan 1999 03:24:12 EST
To: dale_at_unofficialbmw.com
Subject: Lets audio annunciate the loss of oil pressure on my '96 328is & '97 318tis

With a loss of oil pressure on my E36 cars, the oil pressure sender switch closes. This provides a ground to the instrument cluster, which lights the loss of oil pressure warning lamp (idiot light). In our Pratt Whitney F 100 jet engine test facilities we provide an audio alarm, along with a visual alarm, with loss of oil pressure. This feature is relatively easy to duplicate on my current cars by simply running a ground signal to one of the stock chime modules unused inputs. Both of my cars use the same chime module part # 65 81 8 360 995 which retails for $62.50. On my ti only input T3 is used. On my 328 inputs T1, 2 and 3 are used. These three inputs are all ~1000 Hz.

Since the chime module is powered at all times, I ran this added input through a N.O. relay contact. The relay is powered from a hot in run and start line and picked by the oil pressure sender switch. The VDO oil pressure contact has a 2 watt rating (their words). I chose unused input T4 on the chime module, which is a constant ~ 1500 Hz tone (more annoying, which is good) compared to the key in ignition gong pulsing ~ 1000 Hz.

The following is just a guide. Read it completely before attempting this modification. I completed this modification on my '96 328is (build date 4/96). If your car is different, modify the following accordingly. As always, feel free to do it your way. Here we go:

  Pieces parts:

   1 each Relay Radio Shack 12V-1A, 11 ma coil 275-233 $2.49
   1 each BMW female pin 61 13 1 376 202 $1.34 retail
   1 each BMW housing for the above pin 61 13 1 378 460 $2.08 retail

1 each stakon for attaching the ground wire. You will also need wire, Tywraps and the parts for the means of tapping into existing circuits that you use. I remove a small ring of insulation and attach/solder the new wire to it. I seal the junction using Star brite liquid electrical tape. This is available from NAPA in a 4 ounce can # 765-2950 for $5.99.

Remove the drivers side under dash panel. Remove the knee bolster (three 10 mm bolts). Connector X17 is on the left side of the instrument cluster.

There is no need to remove the instrument cluster. The harness is accessible from below. It's right above the left side of the steering wheel column. Connect the wiring as shown.

I made small loops on the relay contacts using my round nose pliers.

X17 pin 19, the .35 BN/GN (brown/green) wire goes to one side of the relays coil. X17 pin 4 the .5 GN/BL (green/blue) wire goes the other side of the relays coil. The ground goes through the relay contact to the T4 input of the chime module. I used shrink tubing over the relay and sealed the ends with a dab of hot glue as shown in the photo.

I picked up ground at the ground point to the left of the dash (10 mm nut). Place the ignition switch in position two. After the seat belt gong the oil pressure one will sound. If it does, good job! When the car is running the loss of oil pressure will light the idiot light and audio alarm together.

RonStygar_at_aol.com FLY BMW Marlborough, CT
http://www.unofficialbmw.com/ronstygar.html
Unofficial RS/SS bender/installer +