The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Installed 70s/80s Cruise Control & It Works!!

**pjmoreland** · 04-16-2005, 01:11 AM

Here's a quick list of the things you have to do. I'll try to take some pictures later:

1) Find a donor van from the 70s (the kind that has the tilt steering column) and get the following parts from it:
-Turn signal lever with cruise button on the end and three wires coming out of it. You can unplug the turn signal lever wires under the dash where the wires come out of the steering column. The wires are connected to a little printed circuit board that plugs into a black plastic connector receptacle.
-Transducer mounted to the passenger side of the engine (has two speedometer cables connected to it). Leave as many of the vacuum hoses connected to it as possible so you won't forget where they go. Label any hoses that you disconnect. Remove the intake manifold vacuum fitting that is behind the carburetor and leave it dangling on the vacuum line for the cruise control. Disconnect the transmission speedometer cable from the transmission and leave it attached to the transducer. The speedometer cable that goes to the speedometer will not work in our trucks, so just disconnect it from the transducer and leave it in the van. If you have AC in your truck, I don't think the van transducer bracket will work. I got a transducer bracket from a 1983 Caprice and mounted it to the driver side inner fender. If you don't have AC, you might be able to use the van bracket, although I don't know this for sure. Disconnect the transducer mount from the engine block. Try spinning the transducer by hand to make sure it spins freely. If it doesn't, you might want to look for another transducer.
-Actuator mounted to the driver side of the engine, behind the carburetor. It's a circular rubber diaphragm with a rod connected to the carburetor. Remove the long post and little clip that connects the actuator rod to the carburetor.
-Wiring harness that passes through the firewall. Leave it connected to the transducer. There is a power wire you will have to disconnect from the fuse panel. Remove the brake light switch and leave it connected to the harness. Disconnect the connector with the orange and white wires (brake lights) and leave it in the van. Remove the vacuum kill switch. It will be mounted right next to the brake light switch. Leave it connected to the vacuum hose. You can now pull the harness out through the firewall and into the engine compartment. If the brake light switch won't fit through the firewall, disconnect it temporarily, and then plug it back in once the harness has been pulled through. The transducer, actuator and wiring harness can now be removed from the van as a single unit

2) If you decide to use a transducer mount from a sedan to mount the transducer on the inner fender, you may want to get an actuator from a sedan as well. The vacuum hose will connect to the driver side of the actuator in a sedan as opposed to straight out the back in a van. I used the actuator bracket from a 1983 Caprice because it also provided me with a place to mount my TV cable for my 700R4 transmission, and the throttle cable in my 1972 truck fit right into the bracket. If you have a throttle linkage, you may need to convert to a throttle cable, since the linkage might not clear the cruise control actuator. I'm not totally certain about this though.

3) Here's what you need to do to install the system in your truck:
-Mount the transducer either in the van position or on the inner fender using a sedan mounting bracket. I let the lengths of the speedometer cables dictate where mine got mounted. You will have to buy a 3 ft. speedometer cable to run from your speedometer to the transducer. The big cable connection on the transducer is for the cable to your speedometer, and the little connection goes to the transmission. I used the standard length speedometer cable for a TH350 transmission for connecting the transducer to the transmission. Make sure the speedometer doesn't get too close to your exhaust. I routed mine underneath the emergency brake cable so that it would be held up on the inner fender away from the manifold.
-Mount the actuator to the engine block either using the van bracket or a bracket from a sedan. You may have to drill a mounting hole in your carburetor linkage to mount the actuator linkage post. Make sure that the post is mounted far enough away from the center of rotation of the carburetor linkage that the post slides the entire length of the slot in the actuator linkage, and no more than this. If the rod moves farther than the length of the slot, the linkage will end up pushing in the actuator when you are stomping on the gas, and the linkage can jam, holding your throttle open partially. Make sure you hold your choke open when testing this. Adjust the actuator linkage so that when the carburetor butterflies are completely closed, the actuator linkage rod is all the way forward in the slot in the linkage. That way the actuator will be able to pull on the throttle as soon as it starts to move.
-Install the wiring harness. The routing is not important. I ran my harness inside the driver side fender where the headlight harness goes, and passed it through the firewall where the throttle solenoid wiring harness used to go. If you don't have this option, you will have to cut a hole in your firewall. I'd recommend measuring the diameter of the hole in the donor van. You can use a hole saw to drill the hole. I used a hole saw to drill a hole for my tach harness and it worked great. You may have to disconnect the brake light switch temporarily to get the harness to pass through the firewall. Plug it back in once you get the harness through.
-Install the turn signal lever. You'll have to pull your steering wheel off to gain access to the mounting screw (a puller is usually required). Remove the plate that covers the bottom of the gauge panel gasket. Remove the plate that attaches to the bottom of the brake pedal assembly. Remove the wire cover from the bottom of the steering column. Route the turn signal lever wire down through the steering column, along with the turn signal/ horn wires. Reinstall the wire cover on the bottom of the column. Reinstall the steering wheel. Leave the two plates off for now. Plug the turn signal lever wire into the wiring harness under the dash.
-Install the brake light switch. Remove the original brake light switch and install the cruise control light switch in its place. The original brake light connector (orange and white wires) will connect right up to the van brake light switch. Make sure the light switch is adjusted so that your brake lights come on when you press the brake pedal down about 1/4".
-Install the vacuum kill switch. I machined a custom clamp bracket and mounted the switch to the top of the square plate that bolts to the bottom of the brake pedal assembly. I positioned the switch so that the front edge of the brake pedal arm pressed on the switch plunger. I used a vacuum kill switch from the 1983 Caprice because it had an extra electric switch that I used to control the torque converter clutch on my 700R4 transmission. I had to adjust the brake linkage a little bit to allow the brake pedal arm to reach the vacuum switch. The vacuum kill switch has 5/8-18 threads, and the first 1/8" of it is not threaded. The mounting block I made has a 5/8-18 threaded hole through the middle of it. I had to carve off the 1/8" of unthreaded plastic so that the switch would thread into the block. You may be able to get away with omitting this switch altogether since the brake switch will disable the cruise control. I suppose the vacuum switch is to make sure there is no possible way for the cruise control to get stuck on if the button fails. If you decide to omit this switch, be sure to plug the vacuum line that connects to it. Personally I feel more comfortable having this switch connected, but you could always stomp on your brakes and worst case turn off your engine if the cruise control got stuck on (highly unlikely, but you never know).
-Hook up the power wire. Snip off the connector that plugged into the van fuse panel and crimp on a female spade terminal. I'd recommend installing an inline fuse onto the end of this wire. Plug the other side of the inline fuse into the location on the fuse panel marked "ignition unfused".

You should be ready to go. Hope this helps.

As a side note, I noticed that the cruise control in the 83 Caprice had some extra wires that connected to a valve that was mounted on the front of the transducer. I'm guessing there was a button on the dash (in addition to the turn signal lever button) that had to be pushed to enable the cruise control system. This type of system would work just fine in our trucks, but would require a little more work than what I have described.

I used my cruise control for the first time yesterday. I used it again this morning on the highway all the way to work. It was very nice! On long drives I have a tendency to slow down slowly without realizing. I find it tedious to try to maintain a constant speed. I guess I'm just lazy.

04-16-2005, 01:11 AM	#6
pjmoreland Senior Member Join Date: Jan 2005 Location: CA Posts: 5,343	Here's a quick list of the things you have to do. I'll try to take some pictures later: 1) Find a donor van from the 70s (the kind that has the tilt steering column) and get the following parts from it: -Turn signal lever with cruise button on the end and three wires coming out of it. You can unplug the turn signal lever wires under the dash where the wires come out of the steering column. The wires are connected to a little printed circuit board that plugs into a black plastic connector receptacle. -Transducer mounted to the passenger side of the engine (has two speedometer cables connected to it). Leave as many of the vacuum hoses connected to it as possible so you won't forget where they go. Label any hoses that you disconnect. Remove the intake manifold vacuum fitting that is behind the carburetor and leave it dangling on the vacuum line for the cruise control. Disconnect the transmission speedometer cable from the transmission and leave it attached to the transducer. The speedometer cable that goes to the speedometer will not work in our trucks, so just disconnect it from the transducer and leave it in the van. If you have AC in your truck, I don't think the van transducer bracket will work. I got a transducer bracket from a 1983 Caprice and mounted it to the driver side inner fender. If you don't have AC, you might be able to use the van bracket, although I don't know this for sure. Disconnect the transducer mount from the engine block. Try spinning the transducer by hand to make sure it spins freely. If it doesn't, you might want to look for another transducer. -Actuator mounted to the driver side of the engine, behind the carburetor. It's a circular rubber diaphragm with a rod connected to the carburetor. Remove the long post and little clip that connects the actuator rod to the carburetor. -Wiring harness that passes through the firewall. Leave it connected to the transducer. There is a power wire you will have to disconnect from the fuse panel. Remove the brake light switch and leave it connected to the harness. Disconnect the connector with the orange and white wires (brake lights) and leave it in the van. Remove the vacuum kill switch. It will be mounted right next to the brake light switch. Leave it connected to the vacuum hose. You can now pull the harness out through the firewall and into the engine compartment. If the brake light switch won't fit through the firewall, disconnect it temporarily, and then plug it back in once the harness has been pulled through. The transducer, actuator and wiring harness can now be removed from the van as a single unit 2) If you decide to use a transducer mount from a sedan to mount the transducer on the inner fender, you may want to get an actuator from a sedan as well. The vacuum hose will connect to the driver side of the actuator in a sedan as opposed to straight out the back in a van. I used the actuator bracket from a 1983 Caprice because it also provided me with a place to mount my TV cable for my 700R4 transmission, and the throttle cable in my 1972 truck fit right into the bracket. If you have a throttle linkage, you may need to convert to a throttle cable, since the linkage might not clear the cruise control actuator. I'm not totally certain about this though. 3) Here's what you need to do to install the system in your truck: -Mount the transducer either in the van position or on the inner fender using a sedan mounting bracket. I let the lengths of the speedometer cables dictate where mine got mounted. You will have to buy a 3 ft. speedometer cable to run from your speedometer to the transducer. The big cable connection on the transducer is for the cable to your speedometer, and the little connection goes to the transmission. I used the standard length speedometer cable for a TH350 transmission for connecting the transducer to the transmission. Make sure the speedometer doesn't get too close to your exhaust. I routed mine underneath the emergency brake cable so that it would be held up on the inner fender away from the manifold. -Mount the actuator to the engine block either using the van bracket or a bracket from a sedan. You may have to drill a mounting hole in your carburetor linkage to mount the actuator linkage post. Make sure that the post is mounted far enough away from the center of rotation of the carburetor linkage that the post slides the entire length of the slot in the actuator linkage, and no more than this. If the rod moves farther than the length of the slot, the linkage will end up pushing in the actuator when you are stomping on the gas, and the linkage can jam, holding your throttle open partially. Make sure you hold your choke open when testing this. Adjust the actuator linkage so that when the carburetor butterflies are completely closed, the actuator linkage rod is all the way forward in the slot in the linkage. That way the actuator will be able to pull on the throttle as soon as it starts to move. -Install the wiring harness. The routing is not important. I ran my harness inside the driver side fender where the headlight harness goes, and passed it through the firewall where the throttle solenoid wiring harness used to go. If you don't have this option, you will have to cut a hole in your firewall. I'd recommend measuring the diameter of the hole in the donor van. You can use a hole saw to drill the hole. I used a hole saw to drill a hole for my tach harness and it worked great. You may have to disconnect the brake light switch temporarily to get the harness to pass through the firewall. Plug it back in once you get the harness through. -Install the turn signal lever. You'll have to pull your steering wheel off to gain access to the mounting screw (a puller is usually required). Remove the plate that covers the bottom of the gauge panel gasket. Remove the plate that attaches to the bottom of the brake pedal assembly. Remove the wire cover from the bottom of the steering column. Route the turn signal lever wire down through the steering column, along with the turn signal/ horn wires. Reinstall the wire cover on the bottom of the column. Reinstall the steering wheel. Leave the two plates off for now. Plug the turn signal lever wire into the wiring harness under the dash. -Install the brake light switch. Remove the original brake light switch and install the cruise control light switch in its place. The original brake light connector (orange and white wires) will connect right up to the van brake light switch. Make sure the light switch is adjusted so that your brake lights come on when you press the brake pedal down about 1/4". -Install the vacuum kill switch. I machined a custom clamp bracket and mounted the switch to the top of the square plate that bolts to the bottom of the brake pedal assembly. I positioned the switch so that the front edge of the brake pedal arm pressed on the switch plunger. I used a vacuum kill switch from the 1983 Caprice because it had an extra electric switch that I used to control the torque converter clutch on my 700R4 transmission. I had to adjust the brake linkage a little bit to allow the brake pedal arm to reach the vacuum switch. The vacuum kill switch has 5/8-18 threads, and the first 1/8" of it is not threaded. The mounting block I made has a 5/8-18 threaded hole through the middle of it. I had to carve off the 1/8" of unthreaded plastic so that the switch would thread into the block. You may be able to get away with omitting this switch altogether since the brake switch will disable the cruise control. I suppose the vacuum switch is to make sure there is no possible way for the cruise control to get stuck on if the button fails. If you decide to omit this switch, be sure to plug the vacuum line that connects to it. Personally I feel more comfortable having this switch connected, but you could always stomp on your brakes and worst case turn off your engine if the cruise control got stuck on (highly unlikely, but you never know). -Hook up the power wire. Snip off the connector that plugged into the van fuse panel and crimp on a female spade terminal. I'd recommend installing an inline fuse onto the end of this wire. Plug the other side of the inline fuse into the location on the fuse panel marked "ignition unfused". You should be ready to go. Hope this helps. As a side note, I noticed that the cruise control in the 83 Caprice had some extra wires that connected to a valve that was mounted on the front of the transducer. I'm guessing there was a button on the dash (in addition to the turn signal lever button) that had to be pushed to enable the cruise control system. This type of system would work just fine in our trucks, but would require a little more work than what I have described. I used my cruise control for the first time yesterday. I used it again this morning on the highway all the way to work. It was very nice! On long drives I have a tendency to slow down slowly without realizing. I find it tedious to try to maintain a constant speed. I guess I'm just lazy.