My cruise control doesn't work. I was told that the yellow wire connects to the odo and that will power the cruise... I just (even in my Haynes) can't figure out which plug or even if it's actually the yellow wire. I had another cluster in my hand from a 1992 and there was a small rubber band around a double plug. I have that same double plug but no band on it. was something not wired correctly?
Mm

 

our 87 cruise control hadn't worked for a long time, and when I finally got around to trouble shooting it, I realized the actuator cable that pulls on the gas pedal was corroded and completely gone.... so its probably a good thing to check the mechanical side of it before chasing down wiring gremlins.

the wiring diagrams are remarkably vague on that yellow wire... one end is pin 5 of the cruise control module, which is a rectangular module just left of the steering column. the other end says it goes to "203" but thats not shown on the instrument panel layout. there's a double connector just to the left of the speedo module and to the right of the circular connector 31 (as you face the back of the combined instrument panel) and near the turn signal indicator lamp, this is for the tachometer and takes a red-white wire from the ignition coil.

 

Mine is a 1990 all of the wiring is extremely sound I can tell that the instrument cluster had been removed because I'm missing the metal clip on the left side of the instrument cluster that holds it in place. I found another diagram where someone had circled double connector and said it was for the cruise control. Certainly there's someone who has a 240 DL with cruise that knows Which wire is supposed to be connected to the Cluster. Thanks for the reply Pierce

 

The yellow wire that goes to the cruise control connects to the double spade on the back of the instrument cluster (the one with the rubber band on it).

 

Awesome thank you very much I can't wait to try it out

 

Okay so I plugged it into the cluster I still get no power to the cruise the light nothing I managed to find a four wire plug that's just loose in the back does I get connected to the cruise module Assuming of course it is there

 

I'm not sure which four wire plug you are referring. According to the wiring diagram, the yellow wire goes from the instrument cluster to the cruise control unit. Follow the yellow wire down and you should find the CC unit. Check the CC unit to see if it is connected or if your extra connector fits.

 

I will try that tonight!! good idea.

Mike

 

http://www.facebook.com/photo.php?fb...type=1&theater

what is this plug?

 

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how do you post a picture here? I have a 5 wire plug behind the cluster where does it go?

mike

 

you can attach the picture, if its not too big, or post it on a photo site like google's Picasaweb, or smugmug, or flikr, or whatever, and copy the URL of the image and embed it in [ I M G ] and [ / I M G ] tags (without spaces, of course).

my 1990 240 greenbook only shows a 6 pin connector 32 with 5 wires on it thats shaped like a smile, and a 12 pin connector 31 shaped like a circle, its pretty obvious where these go, both are behind the gas gauge / water temp. then there's the three pin connector to the speedometer itself, and a couple single wire connectors...

• yellow-red wire goes to a single connector at the lower corner on the vehicle's right side (left side as you face the back of the instrument panel) - this goes to the automatic overdrive yellow arrow
• IF you have a tachometer instead of a clock, a red-white wire goes to a spade on the tach.
• a yellow wire for the cruise control goes to a spade next to the speedometer

 

The alternator is new and it's still not charging. The battery is dash is NOT coming on, HELP PLEASE!!

 

should probably start a new thread for this, as its a different car with a different issue, but whichever.

you connected the skinny red wire to the D+ terminal (aka pin 51) on the alternator? that wire goes through pin 3 of an 8 pin connector near the center of the firewall and then on to pin 11 of socket 31 on the back of the instrument panel which is the circular socket. the other side of the light bulb goes to the blue wire on pin 3 of the speedometer, to the ignition key.. if you disconnect and ground that skinny red wire when the ignition is switched on, the light SHOULD light up. if the light does light up, then there's something wrong with the regulator on your new alternator. if the ligth doesn't light up, replace the light in the dashboard and try again. if it still doesn't come on, you have a wiring problem. that light *HAS* to work or the alternator won't bootstrap itself.

 

Just traced out all the cruise control wires on my 1990 240 and here is what i got.

From the back of the cruise control module:

Black --Ground
Orange ( Return from Pump)
White --To hand Switch "Resune" Goes High when resume is pushed
Yellow -- Speed pulses in from double spade behind Instrument Cluster
Green/ Yellow --return from Pump
White/Black-- to brake Vacume Switch ( goes High when brake is pressed)
Blue== To hand Switch "set" Goes High when Set is pressed.
Blue/Red -- To hand Switch "Power" High when cruise control turned "ON"

Red/ yellow -- Power to pump.


To Test Pump
If you put 12v to Red/Yellow and Ground to Orange AND Grn/Yel pump should run and gas peddle should go down to floor

To Check Speed pulses get a VOM Meter with a herts setting (HZ) and hook to yellow wire.
Should get 80HZ at about 30 MPH and 160HZ at 60MPH, Be careful, get a helpern to drive or read meter.

This is same frequency as wheel pulses in to Speedo.

Mine had good wheel pulses in to speedo but nothing out to Cruise (double spade--yellow wire.

There is some kind of amp or pulse shaping circuit in speedometer to condition wheel pulses for use in cruise but I determined that the Cruise control would operate with pulses over 2 volts p-p using a scope and a pulse generator and injecting pulses into the yellow wire. That was pretty cool because I could get the Cruise control to funcyion with the engin off and parked in the driveway.

The speed pulses off the wheel ( green white wire on 3 connector plug going into the speedometer are about 12V p-p so I disconnected yellow wire from double spade and jumpered the green white going in to speedometer (wheel pulses) to the yellow wire in to cruise and guess what?? IT WORKS
Since this is not standard wiring I am not recomending you do this and you do it at your oun risk but it is a way of verifying that all the other parts of the cruise control are working.
the final correct solution would be to replace the speedometer so that the pulses come out the double spade as they should.

Let me know what you find-.

M

 

Thanks for your info Pierce. I tore up my Cruise control and hooked up a scope and Frequency counter and got some detailed info if you are interested. The 3 wire conn to Speedo is Power, Ground and Speed Pulses from Wheel Sensor ( appx 12V p-p at 10 MPH) The Frequency is about 80 HZ per 30 MPH. They are processed somehow in the Speedo (probably squared up and scaled) and sent out to the double spade to go to Cruise. (this part of my Speedo is broken so dont have details abot the output).
If you Jumper the speed pulses into the speedo to the yellow wire to Cruise (disconnected from double spade) the Cruise Control works just fine. This is a good troubleshooting tool if your Speedo works ok but your cruise control does not.
let me know if you would like more info.
mike

 

If you have diagnosed to this point and jumpering works as you say, the cause of the problem is the taxi output of the 2115 chip on the speedo circuit board is fried. The taxi output is what drives the cruise control (and provides the speed signal to the ECU).

You can replace the 2115 chip on the speedo circuit board and that should restore operation. Just do a google for ITT 2115 and you should be able to find replacement chips.

 

Thanks for this info. Working on my C.Control. Pulled instrument panel and found that the yellow wire was unhooked. Plugged it in and hey, the cruise is working. Thanks for the info.