need help with cruise control Pre-1981.

CrammerGram69

Master Mechanic
Nov 15, 2019
414
132
43
SW, Michigan
I recently contacted M&H Electric Fabricators about a Cruise control harness for my 1979 LeMans. They offer both 1978 & 1979 for Malibu. Would anyone here specialize in the older cruise systems & know the differences in the Wire harness between those two years? (Different site but same product) Cruise Control Wiring Harness, 1978 Chevrolet Malibu If you wanted to see for yourself. Would this be the item that connects to the Brake light switch or where? My car is Non-cruise and i am trying to adapt the original style which would've come with it. (Inner fender transducer). Trying to find someone to help me out. Thanks.
 

ELCAM

Royal Smart Person
Jun 19, 2021
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I have some of a 79 El Camino resume system to go by.

First the harness is sort of like that but there are differences. Most of the colors are not the same on the what's left of the 79 resume harness I have.
Mand H Harness.jpg

1 plugs into the cruise transducer.

2 is +12V.

3 plugs into the turn signal switch handle harness.

4 plugs into the brake light switch.

Number 3 on the factory harness with resume looks like this.
ruise switch onnector 79 with resume.jpg


Also the wiring harness should have a rubber grommet to seal where it goes through the firewall. It also has a vacuum hose running with it one end of it tees into the transducer and the other end goes to the brake light switch.
The grommet goes through the same place in the firewall where the clutch linkage goes. Cruise was not available on g bodies with standard transmissions.

The resume adds another connector that plugs into the resume solenoid that is bolted to the transducer.

Resume transducer with chevy bracket. Don't know if Pontiac is the same.
79 EC transducer with resume1.jpg

Mounts in these two holes on the inner fender.
holes inner fender.jpg

Resume circuit diagram.
RESUME PG 05.jpg

Non resume diagram.
Cruise NR pg14.jpg
 
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CrammerGram69

Master Mechanic
Nov 15, 2019
414
132
43
SW, Michigan
I have some of a 79 El Camino resume system to go by.

First the harness is sort of like that but there are differences. Most of the colors are not the same on the what's left of the 79 resume harness I have.
View attachment 220193
1 plugs into the cruise transducer.

2 is +12V.

3 plugs into the turn signal switch handle harness.

4 plugs into the brake light switch.

Number 3 on the factory harness with resume looks like this.
View attachment 220194

Also the wiring harness should have a rubber grommet to seal where it goes through the firewall. It also has a vacuum hose running with it one end of it tees into the transducer and the other end goes to the brake light switch.
The grommet goes through the same place in the firewall where the clutch linkage goes. Cruise was not available on g bodies with standard transmissions.

The resume adds another connector that plugs into the resume solenoid that is bolted to the transducer.

Resume transducer with chevy bracket. Don't know if Pontiac is the same.
View attachment 220195
Mounts in these two holes on the inner fender.
View attachment 220196
Resume circuit diagram.
View attachment 220197
Non resume diagram.
View attachment 220198
Right on! Thanks, man. I've seen looking everywhere for info and haven't had any luck! Talk about rare nowadays!? Yeah, so the car I'm getting the whole setup from is a 1978 Pontiac Phoenix (Xbody) with the older Blue 231 eng and i assume a Th350 non-tcc. (think that came out in 81?) It does not have Resume on it that i remember. I'll be going out Saturday to remove it all. I've already done the research/part #s work needed from the 76-81 Pontiac Parts Catalog. I'm also curious about the Brake light switch, I can only find 2 Prong connector ones online new. No Singles. :unsure:

The Servo/Regulator was used in a few other cars, from what the book said, and the Bracket, Rod, etc Looked to be 231 Specific. Possibly wiring? As much as i know currently it is a Diamond in the rough 1978-80 ish... Items. But i need to look more into it. The transducer part #s i tracked it down too was used on a couple of other Platforms. I believe the setup on that particular car to be intact. minus the cruise/turn signal stalk in the column. Both My car & that one was Non-tilt. But only the Phoenix had factory Cruise. I'll have too also look at my inner fenders as they're metal vs the newer 1980 or so plastic.
 

CrammerGram69

Master Mechanic
Nov 15, 2019
414
132
43
SW, Michigan
I have some of a 79 El Camino resume system to go by.

First the harness is sort of like that but there are differences. Most of the colors are not the same on the what's left of the 79 resume harness I have.
View attachment 220193
1 plugs into the cruise transducer.

2 is +12V.

3 plugs into the turn signal switch handle harness.

4 plugs into the brake light switch.

Number 3 on the factory harness with resume looks like this.
View attachment 220194

Also the wiring harness should have a rubber grommet to seal where it goes through the firewall. It also has a vacuum hose running with it one end of it tees into the transducer and the other end goes to the brake light switch.
The grommet goes through the same place in the firewall where the clutch linkage goes. Cruise was not available on g bodies with standard transmissions.

The resume adds another connector that plugs into the resume solenoid that is bolted to the transducer.

Resume transducer with chevy bracket. Don't know if Pontiac is the same.
View attachment 220195
Mounts in these two holes on the inner fender.
View attachment 220196
Resume circuit diagram.
View attachment 220197
Non resume diagram.
View attachment 220198
Found this one on eBay. The seller doesn't know the year??? but he did tell me this. The Main hose going from petal to t-fitting is around 53 inches, and the wiring harness is around 49 inches. There is a 3-prong and 2-prong plug under the dash, a 2-prong 1-prong, and another 2-prong under the hood. I think the cut wire is the ground.

I'm thinking 1981+ Seems like too many connections for the older cruise system.
s-l1600.png
 

ELCAM

Royal Smart Person
Jun 19, 2021
1,085
1,200
113
That harness would work, part of the problem is it is a resume system harness. The connector at the top with the terminals at right angles is the transducer connection. The single wire is likely a warning light that only some cars used. The two terminal with the terminals flat is the resume solenoid.

The two terminals inside are the 3 wire connector to the cruise switch in the turn signal lever, the two wire goes to the brake light switch with the vacuum port.

The old vacuum switch is not available but a later version is the GM 25509432 or standard motor products SLS234 Note it also has the divider between the terminals like the one on the e bay harness.

If the price is right I would get that harness it will do the job.
 
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CrammerGram69

Master Mechanic
Nov 15, 2019
414
132
43
SW, Michigan
That harness would work, part of the problem is it is a resume system harness. The connector at the top with the terminals at right angles is the transducer connection. The single wire is likely a warning light that only some cars used. The two terminal with the terminals flat is the resume solenoid.

The two terminals inside are the 3 wire connector to the cruise switch in the turn signal lever, the two wire goes to the brake light switch with the vacuum port.

The old vacuum switch is not available but a later version is the GM 25509432 or standard motor products SLS234 Note it also has the divider between the terminals like the one on the e bay harness.

If the price is right I would get that harness it will do the job.
I gotcha. If i need too I'll try to track down a NOS old version of the Switch. I don't mind paying. As for the harness, for the extra connectors which have to do with the resume would i just need them unplugged? Btw check your PMs i sent some messages regarding this stuff.
 

79 GP 4 speed

Master Mechanic
Nov 12, 2017
447
535
93
I may have the stalk you need and possibly a brake switch. Give me a couple days to look for it. Where are you located?
 
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CrammerGram69

Master Mechanic
Nov 15, 2019
414
132
43
SW, Michigan
I may have the stalk you need and possibly a brake switch. Give me a couple days to look for it. Where are you located?
I am in Lower michigan.
 

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