The following are the steps I took to add OEM cruise control to my manual transmission 93 Civic DX. All parts were purchased at junkyards from 92-95 manual transmission Civic LXs and EXs. Removing the front driver's seat may facilitate maneuverability as you work under the dash.
- Schedule one day at the yard for removing the gas-brake pedal assembly from either an LX or EX. You will need this
assembly because the DX gas pedal does not have the bracket and lever for connecting the CC
actuator cable. Instructions: Remove the lower dashboard (three Phillips head screws holding
plastic cover on; two bolts with 10 mm heads, holding metal cover on). Disconnect the many
connectors to the fuse box. Figure out how they all detach so you do not have to destroy anything when you do the same at your DX later. Remove the
two nuts (10 mm head) that hold the fuse box to the chassis and remove the fuse box. Use a shop manual for directions to remove the steering
column, and remove it. Disconnect the brake switch electrical connector, then loosen the brake switch lock nut. Remove the brake switch. Remove the cotter pin near the middle of the brake pedal arm. Remove the five nuts and one bolt holding the gas-brake pedal assembly to the firewall. These nuts and bolt all have 12 mm heads. Maneuver the assembly out. The following sites may be helpful for this step:
http://www.sandmracing.com/m_el06_cruisecontrol.html, http://www.honda-tech.com/zerothread?id=2090074, and http://honda-tech.com/zerothread?cmd=print&id=1337459
- Schedule one day at the yard to obtain the following cruise control parts. You will end up largely disassembling the driver's side lower
dashboard; see step 1 for directions for this disassembly. Pulling the steering column to remove the parts below is not
essential but will make this step easier.
- Cruise Control Unit (CCU). This is also known as the "cruise control module" or the "CC computer." It is on the outboard side of the driver's passenger footwell. Include the CCU's bracket and the four mounting bolts/nuts.
- Clutch Switch. This is the lower of the two switches installed on the clutch pedal arm. It has a pink wire and a black wire coming from its connector.
- Brake Light Switch. This is 4P on the LX. It is 2P on the DX.
- Main Switch. On the outboard side of the dashboard. Pry it out carefully using a screwdriver with a tiny head.
- Set/Resume Switch. On steering wheel.
- Cable Reel Assembly. This is also known as the "airbag clock spring" and "slip ring." Follow the Honda shop manual's instructions and disassemble the steering wheel to remove this. Respect the manual's cautions concerning the SRS system. You do not want the steering wheel airbag blowing up in your face. You will need a Torx 30 screwdriver to remove the airbag.
- Actuator. Under the hood, driver's side. Disconnect the CC cable at the gas pedal first. Include the bracket that holds both the throttle cable and actuator cable, too.
- So your cruise control installation looks like OEM as much as possible, avoid cutting wires on your junkyard parts and on your DX. Print out and study the chassis wiring diagram that shows the cruise control for your Honda. Take it with you to the yard. The free online repair guide for Civics at www.autozone.com has wiring diagrams, as do many other free sites. But the shop manual will have the most complete wiring diagram for this job. The one I used appears below. Click on it to get a larger version.
- Schedule one day at the yard for obtaining wires (with their connectors intact where possible) for the parts in step 2. As you remove the wires at the junkyard, sketch wire
junctions and note the color and location of the plastic multi-wire connectors
to which they attach. The following observations should help: Every plastic multi-wire connector can be taken apart so that individual wires may be pulled, and such that nothing is destroyed. This is called "depinning." Study each connector and use precision or electrician's screwdrivers to do so. (Harbor Freight was selling a set of precision screwdrivers for $2.19 in 2008.) I found 1.4 mm head and 2.0 mm head screwdrivers to be invaluable. Using them you can remove almost every individual wire's male or female connector end intact. Typically each multi-wire connector has a flap at one end that has to be pried open. At the other end you can access a tiny button inside that has to be lifted. These two sites have excellent illustrations of typical Honda connectors and how to depin them: http://www.in.honda.com/Rjanisis/pubs/SB/B00-039.PDF. http://honda-tech.com/showthread.php?t=1573760. Depinning is tedious, aggravating, good-eyes-required work. The better news is that depinning gets easier as one gets accustomed to the various plastic multi-wire connector designs. I made six exceptions and ended up cutting wires as follows: (a) the green/white wire from the brake switch to the brake lights; (b) the black/yellow wire at the CCU; (c) the main switch's black wire and red/black wire; (d) the yellow/blue variable speed sensor (VSS) wire at the CCU; and (e) the blue ignition coil (a.k.a igniter-tach) wire at the CCU. I guess an alternative would be to pull the entire wire harness on both the junkyard car and your own car. This seems a huge chore, requiring disassembly of the front passenger footwell's various wire harness covers. As an unsophisticated automotive wirer, I am not sure how well I could get it all back together on my DX. On the other hand, many at Honda-Tech.com do what are called "wire tucks," and photos show they are beautiful jobs.
- Remove the DX gas-brake pedal assembly and install the new LX/EX one. Follow the directions in step 1 except make a list of the connectors as you disconnect them. Going by order of removal, write down each connector's location, color, and number of pin slots. This will help you properly re-connect everything later. Attach the CC actuator cable to the new gas pedal. On my DX, there was already a hole in the firewall (with a rubber seal) ready to receive the CC actuator cable.
- Install the brake switch, without its electrical connector for now, and adjust it. To adjust it, loosen fully the switch's lock nut. Rotate the switch so that its plunger advances towards the brake pedal arm. Keep advancing it until the plunger is fully depressed. Then back the switch off 1/4 turn. This should produce about 0.3 mm of clearance between the switch's threaded end and the brake arm pad. Tighten the lock nut firmly. Failure to complete this step properly will send a signal to the CCU that disallows cruise control. Note: This procedure is found in the Honda shop manual under "Pedal Height Adjustment."
- Install the clutch switch, without its electrical connector for now, and adjust it. To adjust it, loosen fully the switch's lock nut. Rotate the switch until its plunger contacts the clutch pedal arm. Rotate it 1/4 to 1/2 turn more. This procedure is similar to the one in the Honda shop manual under the clutch "Pedal Free Play" section.
- Install the remaining parts listed in step 2 in an order that is convenient to you. Attach the wires to the parts. I used one 18-22 AWG straight connector and five 18-22AWG T-connectors. All connectors are available at Radio Shack. In 2008 the T-connectors were labeled "Quick-Splice Connectors... quick connector snaps onto wire, then attaches to male disconnect," part #64-037. Some study of the wiring diagram and tracing of wires at a junkyard LX/EX is necessary to see where the best places to use the T-connectors are. Use a multi-meter and do continuity checks to ensure you achieve proper connections. Specifics of what I did for the more difficult wires follow.
- For the CC actuator wires: Push them through the firewall rubber seal where the main harness goes. Cut a hole with an exacto knife as needed. In the driver's footwell, I took the brown connector on the firewall apart and plugged these wires in. It was not easy working under the dash to do this, but it looks much neater.
- Use a straight-connector to connect the green/white wire at the brake switch to the existing green/white wire that supplied the old brake switch.
- Use a T-connector to connect the black/yellow wire from the CCU to the black/yellow wire on the brown connector mounted low on the outboard side of the passenger footwell.
- Use two T-connectors to connect the dashboard's main switch's black wire and red/black wire to the same wires at the junction box taped on the upper wire harness on the outboard side of the passenger footwell.
- Use a T-connector to connect the yellow/blue VSS wire at the CCU to the yellow/blue wire at the back of the grey connector mounted on the top of the fuse box.
- Use a T-connector to connect the blue ignition coil wire from the CCU to the blue wire at the back of the grey connector mounted on the top of the fuse box.
- Remove the pins and wires for the Instrument Cluster indicator light, since the DX does not have this light built into it. The specific wires to remove are: (a) the CCU's red/blue wire; and (b) the Main Switch's red wire (do not try to unpin the red wire; just cut it).
- Figure out how you will route the wires to the CCU. Open the black plastic covers on the wire harness, and remove wall fasteners as needed. Put things back together only sufficiently to try out your new Cruise Control. This way, if one of the parts is not working right, it will not be so hard to re-access.
- Test drive the car and try the cruise control. Adjust the actuator cable as needed per the shop manual's instructions. I just set my actuator cable's adjusting nuts midway and all worked fine. If the cruise control does not work, then go to the official Honda shop manual's cruise control troubleshooting section. It describes how to test each wire input to the CCU for either continuity or voltage under different conditions. Identifying failed CCU inputs quickly identifies the parts, or the wires to the parts, that are not working correctly. The shop manual troubleshooting page I used appears below. Click on it to get a version that you can print and read.
- If all works satisfactorily, then electrical tape the individual wires
within the harness. Re-install the harness's plastic covers and wall
fasteners. Re-assemble the dashboard. Find some small brackets at the junkyard to use to hold the actuator wires (under the hood) and fix them to existing brackets.
- For further assistance in installing cruise control on your Honda, see http://honda-tech.com/showthread.php?t=2437528
- I naively considered modifying the DX gas pedal so I could connect the CC actuator cable to it. I subsequently found that swapping the entire gas-brake pedal assembly from an LX/EX to my DX is easy.
- A DX cable reel assembly is different from an LX/EX one. The SRS ribbon cable the DX uses is not readily spliceable and so is not easily modified. Just get an LX/EX cable reel assembly from the junkyard.
- I was originally going to cut and splice all kinds of wires. I found early on that crimping and soldering under the dashboard was nearly
impossible. It was also fraught with the risk that the connections might not hold. One alternative is to swap the entire wire
harness from the junkyard LX/EX into your DX, but as I note above, this is a huge
chore. I opted to leave many of the individual wire pins fully intact and so labored through opening multiple OEM plastic connectors. It is hard work, often done under the dash in bad light and cramped space. I ended up using only one crimping butt connector (for one of the brake switch's green/white wires). The Radio Shack T-connectors are much easier to work with. From their design, I have faith that the T-connectors will stay connected. Also, I was able to crimp outside the car the male ends of most of the T-connectors. I think purchasing a ratcheting crimping tool for around $15 at Harbor Freight, especially if you are going to try to crimp in the tight space under the dashboard, is a good idea. See also Wiring Tips.
- The DX instrument cluster does not have a Cruise Control Indicator light. I did not try to rig anything for this. I just removed wires for the indicator light from both the main switch and the CCU. I am used to this indicator light on my 91 Civic LX, but I think I actually prefer not having it.
- I spent about $93 total on junkyard parts and $5 on the Radio Shack connectors. With hindsight (e.g. knowing the junkyards with the best prices and exactly which wires I needed), I think I could have done this for under $75 easily. I spent a lot of time studying wiring diagrams, tracing wires in the junkyard cars, and sketching the wiring I found. I think this job can be completed at a comfortable pace with about ten days of labor.
A photo of the LX/EX gas-brake pedal assembly appears below: