190SL Cruse Control

[Jim Villers]

This might be of interest to old car drivers who are not restoration purists. In preparation for my drive to the 190SL Group convention in Leadville Colorado, I decided I needed a cruse control for the 3,400 or so mile round trip drive. The new add-on cruse units are relatively cheep. I bought mine from JC Whitney ( http://www.jcwhitney.com ) for $99 and installed it in about four hours. If I had to do it again, it would only take one to two hours ... a reasonable learning curve and confusing documentation with no wiring diagrams. I installed it without drilling any holes or cutting any wires. It has wiring connections to the always hot, ignition hot, ground, brake light, and coil negative (points) (I have not connected the panel lights so it is not lit). The other connection is a vacuum line. The final attachment is to the throttle. The unit is about as large as a jelly jar and has a flexible cable for the throttle and sits nicely between the air cleaner and the firewall. I connected the flexible cable on the throttle spring location on the air horn. I needed to experiment with the switch settings to get it to work smoothly. The best setting is for a "light, high powered engine"; it provided very smooth performance (i.e. touchy throttle like mine). The unit is interesting because it will turn itself off if the engine RPM raises quickly. It therefore "knows" when the clutch is depressed because the engine RPM's will quickly rise 200 RPM's and it disconnects the cruse mode. I found this interesting since I did not need to install magnets on the drive shaft for a speed sensor like older units. It came with the magnets but after reading the documentation, cars with manual transmissions could use the coil as the speed sensor. I installed the control switch "loose" in front of the gearshift with the wires under the tunnel rug. Cool.

I can be more specific with wire colors, connection locations, and switch settings if anyone is interested.

[bstreep]

This, I'm gonna have to do! Jim, do you have pictures?

Yes, please included me too! I would like the info to purchse the same kit as you did, from JC.
Thanks
Bryan

[Jim Villers]

Bill …. I don't have pictures but I can describe the installation in detail. The cruise I bought was from JC Whitney ( http://www.jcwhitney.com ) Item # 81ZX0344U and vacuum canister # 81ZX0346R. The kit provided everything required for instillation except for several wire end crimp lugs and electrical tape.

Under the cover of the control unit are six dip switches. I set them as follows: SW1-on, SW2-off (4000PPM), SW3-off (Tach Only), SW4-on, SW5-off (Light Vehicles, High Power), SW6-off (Open System), SW7-on (Coil). There is also a black jumper to the left of dip switch 1; this jumper, indicating manual transmission, should be un-jumped.

Control Unit: I located the control unit between the air cleaner and the firewall. The flexible control cable was secured to the stock air horn by the throttle spring bolt using the "pronged bracket". The cable was connected to the throttle linkage of the front carburetor with a "large holed" bead chain end, positioned between the idler arm and the carburetor linkage rod. A length of bead chain makes the connection. You should find it easer to do than to describe.

The control unit wires were connected to the following locations:

Black: Ground - I used the blinker relay lug screw as my grounding point.
Blue: Coil Negative - I ran this wire under the driver's side air duct to hide the wire.
Purple: Brake light switched - I wired this to the brake light switch on the brake booster.
Brown: Control Switch - *
Yellow: Control Switch - *
Green: Control Switch - *
Red: Always Hot - * I wired this to my remote ignition switch under the dash (my key ignition switch quit a long time ago).
Gray and Black: Magnetic Speed Sensor - These wires were not used.
* These four wires were snaked through the "temperature gage" firewall hole.

Control Switch: I located the control switch next to the gearshift with the wires running under the tunnel rug. I left the excess wire under the rug.

Orange: Ignition Hot (fused) - I wired this to the switched side of my ignition switch. It could have been just as easy to wire it to the hot side of the brake light switch. I removed the plastic connector so that the wires from the control unit would not need to be inserted into the connector (so they could be removed and snaked back through the firewall hole if ever needed). I taped the connector with electrical tape.
Gray: - Dash Lights - I did not connect this wire.
Brown: Connects with wire from Control Unit.
Yellow: Connects with wire from Control Unit.
Green: Connects with wire from Control Unit.
Black: Ground - I used a dashboard ground.

The 190SL has only one vacuum connection and that is the brake booster hose between the manifold and the firewall. I spliced a "T" into this hose and connected a vacuum line from the "T" to the "main" side of the vacuum canister. Another short hose connected the "amp" side of the canister to the control unit.

That is all there is to it. Enjoy "cruising".

[Jim Villers]

After testing, I found that utilizing SW1-off SW2-on (5000 PPM) was a better switch setting than the one above. If anyone is following these instructions, incorporate this change.

[Robby Ackerman]

I saw Jim's setup this evening. Very Nice! I've been driving my 190 SL since 1984 and I can't imagine what it would be like to head off to Colorado with a cruise control. If I make it over Sunday, I'll bring my digital camera and we can take a few pictures to post.

Cheers

Robby

[Robby Ackerman]

I saw Jim's setup this evening. Very Nice! I've been driving my 190 SL since 1984 and I can't imagine what it would be like to head off to Colorado with a cruise control. If I make it over Sunday, I'll bring my digital camera and we can take a few pictures to post.

Why do all my posts, post twice??

Cheers

Robby

[Jim Villers]

Robby ... If you get an "Internal server error", ignore it. Your response to the error causes the second post.