Adding Cruise Control

[Kilian]

Don't know if this is the correct forum to post this question, but how hard is it to add cruise control to an 83 GMC C2500? It's currently got the basic (non-tilt) steering column with basic turn signal lever.

I've got a GM shop manual that shows all of the different components, and a parts catalog coming that would help tell me what the P/Ns are for the components. Is it a matter of tracking down the parts or are there aftermarket kits that work?

 

[75gmck25]

You could track down all the OEM parts and get it to work, but it would be a lot simpler to just buy an aftermarket cruise control. If you have a donor truck I would try to install an original setup, but otherwise I'd save up some money and buy one from Rostra or other seller.

Old aftermarket cruise controls used magnets on the driveshaft and a sensor to get vehicle speed. Some of the new systems allow you to install a Vehicle Speed Sensor (VSS) on the speedometer cable, which is what modern systems use. Older systems also used a vacuum diaphragm to pull the cable and accelerate the car, but I'm not sure what the new systems use. The vacuum systems worked fine, but you usually had to route a vacuum hose to the brake pedal switch so that it would open a port and shut it down immediately if you hit the brakes.

Bruce

 

[1987 GMC Jimmy]

I agree with everything above. I will say that I think the pre-‘84 setup would be more ideal for an OEM style add-on since the brains of the unit sits on the inner fender rather than behind the instrument cluster so there’s easier accessibility. The only thing that would be slightly annoying to deal with would be your brake switch, but that’s less of a pest to me than messing with the instrument cluster.

 

[Dtrain]

I put an OEM cruise control in my 91 suburban from donor parts I picked up online and at a junkyard, I bought the wiring manual and bought the blinker stalk with the cruise control switch attached for about 39.00 , I believe the main harness that passes through the fire wall contains a vacuum line that runs to a vacuum switch that gets mounted next to the brake pedal arm along with an electrical switch , the vacuum line runs to the servo that sits on the driver side rear of the engine manifold which hooks up to the throttle linkage. The other harness runs along the bottom of the dash that runs to a VSS module next to the ash tray mechanism I got another needed module with the inside harness. The vacuum servo can be purchased new or used on eBay, mine was used. Also I purchased the cruise linkage that mounts to the existing linkage from a junkyard. The whole thing has been working perfectly for four years now, I drive five to six hours every six weeks so it really makes my drive easy. I had an aftermarket in my old 97 escort that only last about a year and broke. They never supported it so I decided to go with the OEM on the gmc.

 

[Dtrain]

In addition, the only whole I had to drill was through the firewall under the steering column for the main harness grommet which contains the vacuum line and wiring loom.

 

[yevgenievich]

I have most of the cruise control parts available for sale from a parts suburban. I think the only thing I do not have is the photo sensor that sits on the back of the cluster. And the cruise stalk is damaged

 

[Kilian]

Would there be any difference between the cruise servo for a '83 350 with carb and a '87 350 with fuel injection?

 

[1987 GMC Jimmy]

The only foreseeable difference I can think of is the rod length, but it might be the same. Also, LMC has the cruise control buffer for the back of the cluster. They’re everywhere in junkyards, too. The multi function stalk is very cheap, easy to install and guide the wire through the steering column.

 

[yevgenievich]

Rod length is different. Tbi has longer rod, but can be cut down to work for carb application

Would there be any difference between the cruise servo for a 350 with carb and a 350 with fuel injection?

 

[yevgenievich]

Pretty much complete including the sensor. No stalk.

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[82sbshortbed]

After seeing the pic above. Is this switch for the cruise control? Or for something else?

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[crpntr78]

Pretty sure that's a brake light switch with the extra connection needed for cruise.