Principal advantages: enabling coast function for cruise control, cosmetics, slightly better feeling switches Difficulty: This project is not very difficult except for one or two wiring issues. Unless you are a bit mad, you should disconnect the battery ground while working on this (or any other) electrical system. Note: I was not dealing with cars with rear window wiper/washers, these will entail one extra connection to the separate rear wiper/washer harness. Useful tools:
First obtain donor assembly. You should try to get the socket for the 6 position cruise control connection with some wire still on it, and you must get the multi pin connector (for the wiper functions) on the left side since it is different, also with wire if possible. First familiarize yourself with the general layout of the parts concerned and plan what you intend to do. It helps to have the right tools and some spare bits of wire and connectors. Remove the steering wheel - note it's position so you can get it on straight later. Remove the underdash panel. Remove the piece of plastic under the steering column. Now, to remove the old column switches, proceed carefully. There are three screws that hold it to the column, and there are four different wiring connectors to fiddle with. These come apart with varying degrees of difficulty. The wiper switch connector, on the left side, simply pulls off the switch assembly (pull forward), as does the signal switch connector on the right. The high/low dip switch wires will do this, but are buried a bit under the top plastic column cover. I left them for last and just pulled the switch assembly until that one came loose. The cruise control connector, four pins on the old style, is a few inches forward of the switch assembly, with wires running back to the switches.  Now look at the new switches. The (right side) signal connector is exactly the same. The high/low connector is also the same. The wiper connector is where things start to involve effort on your part. Because the new switch has a different pattern (old: intermittent/off/slow/fast; new:off/int/slow/fast) the pin out and the connector are a bit different. the wires, however, are all color coded the same. What you do here is remove the wires from the old socket (one at a time!) and insert them into the new socket. If you have ever done this before you'll know how and skip to the next paragraph. If not, this works for both the large and small female terminals used prior to 1984 - and strangely enough, for the ones on my donor bits. First look at the end of the connector that the other half plugs into. You will see each terminal as a small thin rectangle - with a notch on one side. You use a tiny screwdriver blade (I ground one down and curved it for this purpose), or needle tool, to reach into this notch and depress the little metal tab that locks the terminal into the connector. When it is disengaged you will be able to pull the terminal out by the wire going to it. This little tab must be raised again for it to grab in the next connector it is placed into. When reinserting, make sure the tab is on the notch side of the slot. Remove all the wires from the old socket. Then remove them one at a time from your new style socket, replacing them as you go with the same color coded wire from the car. Try not to tangle them up, ie keep an eye on what you are doing so you have a neat bundle when you're finished. Now for the cruise control connector. There are two extra wires on the new style - these provide the "coast" function. They are wired in series with the brake (and clutch) pedal switches, allowing you to disable the cruise from the switch - no more tapping the clutch pedal - without the control unit forgetting the previous speed selected, which is what it does if you turn the switch to "off" to coast. The old style connector wires are as follows:
and the new style just have little spots on them, which are: 1 - W 2 - Bl 3 - R 4 - Bk 5 - Y 6 - G The correspondence between these wires is a bit tricky. 1,2,3,4 of the old harness go to 5,2,3,4 on the new one, respectively. Got that? What I did was build a little adapter. I I took my donor's 6 pin connector (car side), the four pin connector from my old switch, and connected the four common wires with solder and shrink wrap. The remaining two wires must be tapped into the pedal switch wiring if you want the coast function to work. First identify the cruise control switches on your pedal mounts. They are identical, they are the ones with vacuum lines connected to them. Pull off the one that goes to the brake pedal. Using a test light, identify the one that has 12V when the brake pedal is depressed. You connect this wire to terminal #6 of the new connector. Then terminal #1 of the new connector attaches to the brake pedal switch. Again, I built a little adapter out of spare parts, using a two pin socket from who knows where and another two pin connector. So when I was done I had an adapter that started with the 6 pin connector to mate to the new switch assembly, and went a few inches to a 4 pin connector to plug into the old car connector, and had another foot or so of wire with a male and female set of two pin connectors to attach to the brake pedal switch and it's old feed wire. Now you start connecting wires. The high/low connector comes first, since it's in the way of installing the switches. Then push the switches carefully into place, and lead the signal and wiper connectors into place neatly and push them on. At this point it should be easy to screw the switch assembly down nice and tight. While you're under there, check the socket head cap screws that hold the ignition switch in place, one of mine was a bit loose. Connect the cruise control adapter to it's appropriate places, tucking the extra wiring neatly behind the dashboard. Before going further, you should check all but the cruise control for function. Reconnect the battery, turn the key to on, and run the switches through their cycles. All ok? Good. You can't check the cruise without driving at least 30 mph, and that's hard to do with tools, wires, bits of the dashboard, and steering wheel lying all over the driver's seat. I decided to be courageous and button it all up before testing it, but you could just move everything out of the way, put the steering wheel back on and go for a quick spin. At this point you replace the lower column cover, the underdash panel (panels if you still have the funky cardboard one as well!), the steering wheel and the horn button - don't forget the wire that connects to the horn pad. After determining that everything still works, putting away the tools and filing the various leftover parts, you're pretty much done. |
