Electrical Systems


Some tips to assist in maintaining your electrical system …

Table of contents

  • Power for in-car accessories
  • Fitting a manual radiator fan switch - MY & Brumby
  • MY, MV Brumby - Tail-light reflector Enhancement
  • Reading the Select Monitor engine diagnostics
  • Reading the data
  • Using the select monitor protocol
  • Error Codes

Power for in-car accessories

The old Cigarette lighter has come a along way as a convenient plug-in for modern accessories, however the old wires going to it do need a little more attention & may require rewiring and upgrading with fuses …

Fitting a manual radiator fan switch - MY & Brumby

Driving the early model Subaru's through deep water can cause the electric fan to "swim" through the water and cut into the radiator thus costing a fortune. The fix for this is to add a switch to manually turn the fan off. It also is only a little more effort to manually switch the fan ON. When climbing long hills in low range the coolant fan can be helpful in advance of the load/temp. The original switch {non A/C} turns on the fan at around 98degreesC This is a bit hot when being driven hard, the coolant is boiling before the fan takes full effect.
Before you start you will need about 5M of 10-15 amp wire suggest two colours, a soldering iron and solder, heat shrink, wire cutters and strippers. The switch will need to be a three way type i.e. an off position and two on positions. If you are keen you can buy a backlit switch, the options are limitless.
1. Find the switch screwed into the radiator, its at the bottom RH side of the rad. 2. Unplug the wire off the back {there's only one}. Cut the terminal off and strip enough wire back to join your new wire onto. Join on one colour and heat shrink. 3. Join the other coloured wire on the radiator switch, you can re-use the terminal you cut off the original wire. New terminals are readily available at spare parts shops. 4. Feed the two new wires through the engine bay and through the fire wall. I used the hole for the throttle cable, there are plenty to choose from. 5. Find a good location for the new switch, i used the flat panel next to the ignition switch. Mount the switch leaving room for three new wires. 6. run the two new wires under the dash to the switch and cut off the excess. Use the excess wire to make an earth wire. I used a self tapping screw and a terminal underneath the RH kick panel/trim. 7. Terminate all the ends of the three new wires. The only trick to this is plug the wire from step two on the middle of the new switch and the other two on the two remaining terminals. 8. Turn the ignition on and test, one position should turn the fan on manually. The "automatic on" position can be tested by leaving the ignition on, removing the new wire off the radiator switch and earthing this wire to the body. Keep in mind that the fan next to your hand should start as soon as you earth the wire.
Its probably a good idea to mark the switch positions at this point.
This procedure should not change if the car is fitted with A/C.

Tail Light Reflector Enhancement , MV Brumby , at least

Make a noticeable improvement ( 25%? ) on the silver frosting used to reflect the light from
the bulb in tail light assembly
Use light weight silver foil wrap, ( flower wrap), NOT aluminium foil from the kitchen. Cut roughly to size and cover each facet of brake and indicator compartment, reverse is optional. One facet at a time smear with silicone, stick foil in shiny side up, press into place and trim with sharp blade. For the main back facet an option is easier to coat a piece of flexible plastic such as ice cream lid and stick in place as a curved reflector. Do one side , then compare. Back up against wall and see difference in the glow. If you have a Lux meter measure the difference and post it here please !

Reading the Select Monitor engine diagnostics


All Liberty ECUs post 1989 have what is known as a select monitor port. Two of the signals from this connector are actually a computer serial port that can be used to read information from the ECU.
For example:
• Battery Voltage
• Vehicle Speed
• Engine Speed
• Coolant Temperature
• Ignition Advance
• Airflow Sensor
• Engine Load
• Throttle Position
• Injector Pulse Width
• ISU Duty Valve
• O2 Average
• O2 Minimum
• O2 Maximum
• Knock Correction
• AF Correction
• Atmospheric Pressure
• Manifold Pressure
• Boost Solenoid Duty Cycle

Reading the data

The ECU can be communicated with via a 5V TTL RS232 Serial interface, running at 1953 baud, 8 data bits, 1 even parity bit and 1 stop bit. This electrical interface is not directly compatible with a serial port from a PC so a level converter must be used to read the ECU via a PC. Due to the unusual baud rate not all serial ports will be able to be used. I use a USB->Serial converter (http://www.dontronics-shop.com/product.php?productid=16139&cat=0&page=1) with the FTDI chipset, sold by Dontronics (http://www.dontronics-shop.com).
Missing image

Sample schematic for level converter

Software to read the ECU is available HERE (http://www.vwrx.com/index.php?pg=selectmonitor)

Using the select monitor protocol

For those of us who are a bit more adventurous these are the details on how to use the select monitor protocol.
…to be continued…

Error Codes for early EJ series (Liberty/Legacy/SVX/Impreza/OB)

More info can be found here : http://www.ausubaru.com/forum/showthread.php?t=14372


to this page: web archive, TOONGA, 60766244, Bantum, AlpineRaven

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License