Cruise Control Not Working.
 

i swapped the underhood cruise control unit, and the switch inside onto my 1986 rx7 that originally came unequipped. cruise is not working and the light inside is not coming on. is there something i am missing?

A good fuse?

EDIT: The Meter Fuse. Third row up, third fuse from your left as you look into the box.

If it's not that, then you need to get a meter out. Take the plug off the switch. Turn the key to ON,. See if you have batt voltage on the BY (black/yellow) wire on the plug.

If you have 12v or so, then put that plug back on the switch. Go to the cruise control unit. PUll the plug off. See if you have 12v on the GY wire (green/yellow). If you do not, then push the cruise switches MAIN button and see if you now have the 12v on the GY wire on the control unit.

Write back with the results.

Another thought is that the bulb is spent in the switch. In that case it might be that the Stop switch is sending 12v to the cruise control unit inhibiting cruise or the same thing with the Clutch switch. Not at all unlikely with the clutch switch. I'd go for the other things in this post first.

Do you have a diagram? Cruise Control is really easy. I've done swaps to cars without cruise, put series four in series five etc. Mixed switches b/t series.

We trust you've checked the obvious. The vac hose is connected and has vacuum? The cable is connected to the throttle body linkage etc. All three plugs are on etc.

OH! Did you install the cruise control unit. I saw mention of the switch and the underhood unit........but no mention of the Cruise Control Unit. Next to your left foot. YEAH!

That would be my guess as well.

-=Russ=-

didn't know there was such a thing. what does it look like? does it have a part number?

I'd guess it's about eight inches long, about 4 1/2 wide. It has ONE electrical plug. A 13 socket plug at that. It is located just aft of the interior fuse box. Mine are more or less gold anodize in color.

Most of these cars, even though not equiped with all the extras, have the harnesses and plugs. Just need the parts like the Cruise Control Unit, Acutator and Switch.

It has a part number. You can find it at this site http://www.mazdaformance.com/rx7parts.htm it's not worth my time or yours to look for the part number. Go to the wreck yard and get one. Take a 10mm wrench with you for the bolt. Done

I installed cruise on my 88 that didn't come equipped originally.

The three pieces needed are the under hood unit (plugs into the harness, has a cable to hold the throttle and a vacuum line), the switch in the dash (one plug) and the control unit (one plug).

The control unit is mounted right next to your left ankle if you place your foot on the dead pedal on the far left.

The plug hooks up to it from the bottom (6 o'clock to the unit). It is held onto the car with 2 nuts and the studs are present, permanently attached to the car.

Get into your car and look for the studs and harness plug that isn't being used in that general area. This way you will have an idea where to get the control unit from the donor car, assuming that is how you are getting the parts.

my underhood unit doesn't have a vaccum line. where does it come from? anyone got a pic of where the vaccum line comes off the actuator and where it goes on the engine?

Ah. The TurboII came with an all electric unit. Maybe go to the vac line for the air bypass valve and put a plastic tee in that line and there you are.

i pulled all my parts from my turbo 2 parts car. if the turbo 2 can run cruise without a vaccum why can't my non turbo car do it?

On a S5 model, it was an electric setup. No vacuum line. The S4 models used a vacuum assist method.

There's still no reason for not installing it on your car, if that is worrying you. It can be done.

There are two types of cruise control actuators. The vacuum driven kind is round, and has a vacuum nipple on it. The electrical kind is more of a square box, and has no vacuum nipple. They both bolt up the same way, and both will run the cruise control just fine. I don't know if there is a difference in the cruise control computer between the two (haven't checked into it).

Once you have the cruise control actuator in place & run to the throttle, the cruise control ECU plugged in, and the dashboard switch installed, it should work.

-=Russ=-

kick ass guys!! got it working. it was the box underneath the dash that i was missing and thats why the light on my instrument panel wasn't coming on. the cruise feels a little notchy is that just symptoms of the rx-7 cruise control? thanks for everyones help--jeremie

Explain "notchy". I never had any problems with my cruise. Always worked fine.

The electrical one has no notchy feeling. BUT one of my vacuum ones is, I guess you could say notchy in the sense it speeds up a few mph over the selected speed then returns to the selected speed. I always assumed that was something I could adjust out someday when I didn't have more important things to do.

It's using 15+ year old computer technology in the controller, and 15 year old actuators.

You might have some success lubricating the actuator.

Even so, my cruise control is still a bit "notchy" - it's not as finely controlled as, say, a 2004 Caravan's cruise control. It will vary speed somewhat on hills, and occasionally "get behind" on an uphill. I just chalk it up to the fact that it's quite old technology.

-=Russ=-

I meant to add that the notchy feeling I have only happens at the initial setting of the speed with the vacuum operated one. Once set I notice no problems. Notchy to the author of this thread might mean another thing entirely.

Yeah..mine did the same as Hailers. Described it to the "T". Never really worried about it. Better than using the other cruise control.....called....your FOOT! :p: