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DaleClark's Guide to Cruise Control

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Old 04-08-13, 07:15 PM
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Thumbs up DaleClark's Guide to Cruise Control

OK, I just got done doing a HUGE round of troubleshooting on a friend's (Jon's) cruise control and FINALLY figured this joker out. Figure I'd share what I learned.

First, let's go over the parts of the system.

1. The Actuator. This is the part under the dash of the car. It has a motor that pulls a short throttle cable going to the throttle body. It has a 4-wire connector.

2. The Control Module. This is a small silver box behind the driver's side kick panel, just above the black CPU module. It's held onto the body with 1 10mm nut on a stud and 1 10mm bolt. It has a 30-pin or so connector.

3. The Clutch Switch. This is on the clutch pedal, there are 2 switches. The one that's easy to see is the one for the ECU. The other one is higher up and is a black box with a white plunger, this is the switch for the cruise control

4. The Brake Switch. There's only 1 switch with 2 connectors. The larger, thicker gauge wire connector is for the brake lights. The small white connector with thinner gauge wire is for the cruise control.

5. The Control Buttons. These are on the stock steering wheel, have the Set, Resume/Accel, and Cancel functions. They connect with a 2-wire connector and that signal runs through the clockspring on the steering wheel hub.

6. The Master Switch. This is the switch beside the gauges, has the On and Off master switches for the system.

7. The Speed Sensor. This is on the transmission and puts out a pulse signal to the speedometer that is then turned into a speed signal. This signal is fed to the cruise control and the ECU.

8. The "Cruise" Light. This is on the tach, a green light that says "CRUISE" to show when the system is active and for troubleshooting.


OK, let's go through each component, examine failure modes, and how to test.

1. The Actuator. From what I can tell, these suckers are pretty hardy. I think they could strip out or go bad, but they're solid. The cable needs to be properly installed with a little bit of slack. If it's off the throttle body, it ain't gonna work.

2. The Control Module. If it's not there, or not plugged in, that could be your problem. I think this is like the ECU in that they RARELY fail unless you do something really stupid with it.

3. The Clutch Switch. One common problem here is the rubber feet the clutch switches touch on the pedal. They, over time, will disintegrate and you'll find them on the floor. Go to Lowe's or Home Depot and hit up the hardware aisle, you can find small stick-on rubber feet to replace the stockers. They work great, are dirt cheap, and last a very long time. The clutch switch itself is pretty hardy, the lower switch has a spring that can fail that can be easily fixed with the spring from a click-type ballpoint pen - search on that.

4. The Brake Switch. This was the culprit in the problem I was working on. New ones are only about $35 or so, part number br70-66-490a. It has a red plunger that the brake pedal contacts and a 17mm lock nut - to adjust, disconnect the 2 electrical connections, loosen the lock nut, and screw the switch in or out. You want it adjusted so the whole red switch is fully pushed into the switch. But, you don't want it preloading the brake pedal, just turn it until the red is all gone and set the locknut and plug the connectors in.

5. The Control Buttons. These are very hardy, nothing fancy here. Each button generates a different resistance on the 2 wire circuit when it's pressed.

6. The Master Switch. Again, very hardy, if it's unplugged or something or physically broken that's your problem. The "on" light should light up when it's pressed and it should stay on.

7. The Speed Sensor. This is pretty hardy, but the connector or wiring could be damaged from a clutch job. If you have a PowerFC, real easy to just look at the speed reading on the Monitor screen to test it. If it displays speed, you're fine.

8. The "Cruise" Light. This isn't necessary for the operation of the system, but is needed for troubleshooting. Cars that didn't come with cruise control don't have this light. It's on the lower half of the tach.



Mazda designed a testing system for many of the systems, they're outlined in the Body Electrical Manual, section Q. Some tests show them using Mazda's special computer, but others do a light blink code with the Cruise light. If you don't have a Cruise light, you can rig one up at the cruise module for testing purposes.

To check for service codes, turn the key to On and turn On the master cruise switch. Hold down RESUME/ACCEL on the steering wheel for 3 seconds, then let go. The Cruise light will light for 2 seconds, then go dark if there are no codes. If there are codes, it will start flashing them.

This is like reading Check Engine light codes, a long flash is the tens digit, a short flash is the ones digit. Long-long-short-short-short is 23, for example - 2 longs, 3 shorts. The cycle will repeat once it gets to the end of the codes.

Codes are -

1 - Defective wiring, Defective ground, defective brake switch. This was the code my buddy was getting with a bad brake light switch.

5 - STOP 20A fuse blown. The fuse is blown, replace it. If it blows again, you have a short somewhere or something really messed up.

7 - Stoplight and Brake switch on simultaneously. This means the brake switch is REALLY bad, replace it.

11 - Defective cruise control switch. The cruise switch is shorted out, always acting like Set is held down. Could be a short or the switch.

Next, you have switch tests. These are a troubleshooting aid, NOT the end-all, be-all. The problem car I worked on passed the brake switch test, but it was the problem all along.

To do the switch tests, turn the key to On, engine Off. Put the car in gear, not in neutral. Turn OFF the cruise main switch. Press RESUME/ACCEL and the main On switch at the same time and let go, the Cruise light will come on.

Tests -

Press SET/COAST switch, Cruise light will flash code 21

Press RESUME/ACCEL switch, Cruise light will flash code 22

Press brake pedal, Cruise light will flash 31

Shift into neutral, Cruise light will flash 35

Start the car, drive the car above 25 MPH, Cruise light will flash 37.



So, you don't have cruise control in your car and want it. Good thing is Mazda wired all the cars up for cruise. You need -

- Actuator motor under the hood
- Cruise control cable
- Control module
- Steering wheel switches
- Main switch

Install all those, you should be cruisin'.



If you have an aftermarket wheel, you're in a tougher situation. There are a few options available.

1. Take the stock switches and find a way to mount it on the aftermarket wheel or somewhere else in the car. This will require some wiring and fab work. It has been done in the past.

2. Buy a hub with the buttons. I have an HKB "boss kit" steering wheel hub on my car that has, on the top of the hub, the 3 cruise control buttons. Part number is OR-221. This is a VERY JDM product, I have NO idea how hard it would be to get your hands on this. The hub works wonderfully, lets you use Momo-style wheels, retains the clock spring correctly, everything. I found mine barely used on Ebay a while back. No, you can't have it.

3. Buy a horn button with the buttons. I have had 2 of these in the past. They're a standard Momo-style horn button that have the 3 buttons in the middle of the horn button. Works wonderfully, has the right connector inside to plug in and go. It's VERY rare to find them, though. I'm not even sure who makes them, again a very JDM part.



So, why all this fuss about cruise control? So you don't get a dead leg DRIVING YOUR FD TO DEAL'S GAP ROTARY RALLY! Stop making excuses and GO, it's the best car event I've ever been to!

Hope this helps you guys out!

Dale
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Old 04-09-13, 09:14 AM
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Update on this -

My buddy's car that was having cruise issues that was the impetus for me figuring all this junk out is now good to go. After swapping parts around and doing all kinds of craziness, turns out his brake switch just needed to be adjusted.

I found that the brake switch actuates first for the brake lights and second for the cruise control. If the plunger on the switch is halfway in, it will trip the brake lights like it should, but it won't be far enough to satisfy the cruise control. This also could be a case of it just wearing over time and the resistance of the one spot increasing, moving it to a new spot further in did the trick.

Long story short, start with that. Takes 2 minutes to either use a jumper to bypass the switch and test it or adjust it so the plunger is fully depressed. That would have saved me a ton of time swapping and testing tons of components.

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Old 04-09-13, 10:30 AM
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Dale, another Great Writeup!

We have the error 1 code so now to test that brake switch.

A similar writeup on ABS troubleshooting would be awesome.
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Old 04-09-13, 11:22 AM
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I'm hoping *not* to do an ABS writeup as mine works fine and everyone around me's ABS works fine. I'm OK with not knowing everything about that system .

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Old 04-10-13, 11:21 AM
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Talking

They should give Dale his own section for posting (Dale Clark's Guides for the FD)

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Old 04-10-13, 11:28 AM
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Dale thanks for the writeup.

I put a link to this thread in the FAQ section.
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Old 02-21-14, 01:47 PM
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Does anyone know where the steering wheel switches plug into? all I have is a 4 inch harness coming off of the buttons. Iv'e been told it plugs into the clockspring but I cannot see where. This is for my 94 touring that I bought with aftermarket steering wheel.
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Old 02-21-14, 09:13 PM
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Dale do you happen to know what the resistance values on the steering wheel are? I have an Rx8 steering wheel and I have been trying to find a solution that allows me to integrate the Rx8 buttons to work with the FDs system.
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Old 02-24-14, 10:58 AM
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Rotorhead, it's possible the previous owner removed that connector. It's a pretty obvious white connector.

lnbrown, the resistance of the buttons is in the shop manual.

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Old 02-25-14, 01:23 PM
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^Thanks. Don't know why I didn't think to look there smh.
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Old 03-02-14, 05:25 PM
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actuator rattles

My cruise control works just fine but the actuator has a really annoying rattle that seems to be coming from inside the sealed motor housing. It buzzes/resonates loudly at certain rpms and sounds like a bad old mechanical tach or speedo. It doesn't matter if the cruise is on or off. I don't see an easy way to get inside it. Has anyone else dealt with this sort of complaint? Should I just replace the whole unit??
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Old 05-11-14, 10:12 PM
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Question. I did a 5 speed swap and my cruise control no longer works. Any ideas?
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Old 06-13-14, 09:27 PM
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Great write up. Using this guide I pinpointed my cruise control problem (code 1) at the brake switch, found that the stop for the pin was missing, and repaired it in about 10 minutes!
Thank you.
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