Porsche 944 - Cruise Control Repair Tutorial

[@pele994]

Dude do you have a patreon? You're like a living repair manual, and hell those cost money, but I'd much rather give it to you. This catalog you've been building the past few years is extraordinary, and I thank you for your experience and service.

[@NC944er]

Thanks man, that means a lot! I have the beginnings of a Patreon page, but I need to clean it up a bit before launching. I’ve been pretty slack on the monetization aspect, but you’re not the first to want to contribute to the cause… and I have to admit it would help keep things going on the car and cover some parts cost. I’ll let you know once it’s active. 👍🏼

[@NC944er]

Hey man! Here it is by popular demand... the official NC944er Patreon Page - www.patreon.com/NC944er

[@chabat124]

What a great video. Professional, to the point... no rambling to make it long, no stupid music. I will be subscibing to your channel. I bet it takes a while to make a video that is so clean, well lit, everything in focus, very well edited, text and arrows. Man, excellent work!

[@NC944er]

Yeah man, thank you! Each video is quite the undertaking… with the shooting, processing, organizing, and editing, they generally take about 4 times longer than the actual work on the car. With the niche market they serve and the lower view count, it’s definitely a “community service” gig. 😂 But if they help some folks out with their 944s, it’s all worth it in the end. Thanks for the sub!

[@ok.944]

I was following along the video in my 84' since my cruise control didn't work. First supect was the computer, turns out, its not there. Wouldn't have know without the video lol. Love this channel as a young enthusiast. Helped me through thick and thin, the community thanks you. :)

[@NC944er]

That’s hilarious! It’s crazy the amount of random parts missing on these cars from prior owners. 😂

[@troyschooler3280]

Thanks mate. You are the best. I took my circuit board out and reflowed it with a heat gun on my 1989 turbo and now the cruise control works perfectly..

[@NC944er]

Awesome! Glad it worked out. 👍

[@lizard944]

Just did this blanket solder job and it worked great!.. My CC wouldn't engage when the weather was cold. Classic capacitor problem, or so I thought. About five years ago I replaced those two blue axial caps 2.2µm 63V and that worked at that time. I figured this was the same problem. I pulled those caps and checked them but they were well within specs. Even put them in the freezer with the meter hanging outside and they still didn't go below specs. I diagnosed a garage door safety sensor this way. Green LED would get very dim when cold. Door wouldn't open. Placed a hair drier by the sensor, after a few minutes, worked fine. Changed caps, fixed. I was too lazy to pull the other caps on the CC board so I tried your heat gun approach. I didn't realize how hot the board was getting until I stopped and then saw that the board was smoking...LOL! Anywho, took it for a test driven not expecting much, but it functioned perfectly! Going to the Porsche Swap Meet in Carlisle, PA, next weekend and didn't cherish the thought of no CC during the 500 mile trip. Thanks !!! Your tutorials are legendary!

[@NC944er]

The smoke coming off the board is how you know that it’s working. 😂 No, but I believe with mine there was just a bit of smoke coming from the protective coating on the underside as well, everything else seemed fine. I’m glad it worked for you and hope it holds up! Cheers and safe travels!

[@tims_4x4_garage]

Nice job as always. I put my car on a diet a long time ago and this stuff disappeared with a handful of other things lol

[@NC944er]

HA! Trimming some fat, huh? 😂 Reminds me if my mountain biking days and upgrading from aluminum to carbon fiber components to shave a few grams.

[@tims_4x4_garage]

@@NC944er wasn’t really to save weight, just to clean up things. Anything that didn’t work was fixed or removed completely. Cruise was one of the things that got deleted as was the rear wiper and brake pad sensor system

[@NC944er]

@@tims_4x4_garage Yeah, real men don’t need wear sensors. 🤣 And the rear wiper isn’t terribly useful, other than for creating another water entry point into to car.

[@tims_4x4_garage]

@@NC944er and deleting the rear wiper shaves 4 lb of lopsided weight off of the hatch hinges.

[@tims_4x4_garage]

@@NC944er unrelated I posted my car for sale on Instagram yesterday

[@Boom10ful]

I desoldered and resoldered the entire board on my 944 two weeks ago. Performed a complete capacitor and IC chip replacement since I was in there. Am really impressed on how smooth the cruise control system works compared to my modern car! I just finished my instrument cluster refurbishment and will move onto a complete refurbishment of my DME next week.

[@NC944er]

NICE! That sir takes some serious dedication, well done! Do you have a background in electronics? I agree that for a semi-mechanical system, the cruise control on the 944 is surprisingly good… when the board is working. 😂

[@Boom10ful]

I started off repairing Game Gears in my spare time and have learned how to repair electronics on my own. Just as a hobby of course but I like it! If you ever have issues with your speedometer, replace the capacitors that are in there. Found one that was way out of spec and leaking as well.

[@NC944er]

@@Boom10ful Game Gear! I had one of those! 😂 Thanks for the tip on the speedo, lots of little electrical gremlins to be found.

[@petervermilyea6490]

Stumbled across your video after fiddling with a non functioning cruise control system with no success. Even the Porsche specialist was at a loss as to what is wrong. Can’t wait to try out the heat gun idea and see if that works. Thanks for posting!!!

[@NC944er]

Yeah man, let me know how it goes! 👍🏼

[@petervermilyea6490]

I did the resistance and voltage tests you suggested and on the lower connector I got 55ohm between terminals 5 and 6. I took apart the throttle control module in the engine bay and didn’t see anything amiss. So does that mean I should just replace the throttle control module?

[@NC944er]

@@petervermilyea6490 Mine was reading 49ohms there, so slightly out of spec as well, but my guess it that has more to do with corrosion/oxidation on one or more grounding points or within the servo itself (rust increases electrical resistance). Cleaning all the grounds around the car may help. While the servos “can” fail, more often than not it is the control board that is the issue… at least from what I can gather from the experience of others.

[@GenFool]

Keep it up! Would love a transaxle remove/install vid!

[@NC944er]

If you pray to the car gods for my clutch to fail, you must just see such a video! 😂

[@rrassoc]

Amazing! What problem did you specifically have? When I engage my cruise control, the car accelerates without stopping, until I press on the brake, or turn it off. It never occurred to me to press the clutch, thinking the engine would over-rev. In any case, something works, but something else not so much. Now I have some information to work with. Thanks so much, yet again.

[@NC944er]

Hey! In my case, the cruise control completely stopped working, would not engage. Acceleration beyond the preset set speed is normally an issue with the servo mechanism, but yeah, this should provide an overview of the main things to check out.

[@rrassoc]

​@NC944er I replaced my servo unit with an inexpensive used one through eBay. That didn't help. I don't have a heat gun. I think I'll dedicate that $ towards a replacement computer.

[@rrassoc]

My replacement control unit is working! I have to say, the R&R process was crazy difficult for me. I'm a little too large to get under the dash in a position to see the position of the studs holding the unit in. But this video prompted me to do the job, so thanks again. Look for a new Patreon member soon. 👍

[@phillippasena1429]

Nice video. I have a question about the grounding on the brake lights and how they may impact other areas of the car if the grounding is not correct. I don’t know if you remember, I shared with you that I am having issues with the AC blower and windows operating. 99% of the relays are brand new and all the fuses look clean and healthy. However I recently worked on my passenger side break light I’m wondering if that is affecting these areas. What do you think? again thanks for the awesome video. Oh yeah, I am not going to change out my engine harness, it looks really crazy to replace it.

[@NC944er]

The fresh air blower and window motor functionality should be unrelated to the brake light work. The only other thing on the cruise control circuit would be the antilock relay if your car has ABS. Grounds in general can have an impact on a number of things so if you haven’t done so already, I’d start by checking and cleaning ALL the grounding points inside the car and in the engine bay, which can improve things across the board. Here’s a link that has most of them highlighted - rennlist.com/forums/924-931-944-951-968-forum/445827-how-many-ground-lugs-in-the-interior.html

[@masonbarnes1971]

Just found out I haven’t had brake lights since I got my 944 in December. Caused by a bad connection in the cruise control system

[@NC944er]

Oh man! I’m glad I posted this then… wouldn’t want anyone rear-ending your 944. 😳

[@samchao8842]

Hi NC, I have an ‘88 944 as well, guard red. Very sentimental too me and want to restore back to its glory days and hope to give it to my son. I’m in Durham NC, and want to see where about are you in NC and see if your interested in taking on another 944.

[@NC944er]

Hey Sam! Very cool, my middle son thinks he’ll some day inherit mine. 😂 I’m over in the Burlington area… so not too far from you. Is your car running currently? What are you looking to have done on it? If you’re willing to leave it with me for a week, I could easily bang out a belt job or whatever for a nominal rate (FAR cheaper than the $150/hour Porsche tech rates). Let me know what you think.

[@samchao8842]

@@NC944er Hi NC944er, thanks for your reply and your offer. I’ll take up on your offer. The car hasn’t been started up for ~10 years or so, it’s been sitting in garage, so probably need lot of work and also very interested in restoring the engine bay like in one of your other video. Let me know how to reach you and we can set up something. Thanks Sam.

[@NC944er]

@@samchao8842 Ok, that’s a bit more extensive than I was initially thinking. The safest bet to proceed would be to change the timing belt and engine fluids before attempting to start it up. It’s also best to clean out the fuel tank, replace the strainer, and test the injectors (they tend to get stuck after sitting). These steps will ensure that things aren’t damaged when bringing it back to life. Since it’s not drivable, I’d either have to work on it at your place, which would be difficult with my schedule, or have it towed to my garage. I’m afraid I don’t have the time for that level of restoration at the moment, but perhaps later this year. I’ll let you know.

[@samchao8842]

@@NC944er I understand, I can have it trucked to you place and you take your time based on your schedule, I’m in no hurry. If your still interested, let me know how to reach and we can talk about the details.

[@NC944er]

@@samchao8842 Ok cool, that sounds good! My email address is listed in the "About" section of my channel at the bottom of the page under "Details." Feel free to hit me up there and we can exchange numbers and set up a date in the future for me to come look at the car.

[@notnilc20]

What was wrong with your cruise control before the fix? mine just continues to accelerate even after you release the handle.

[@NC944er]

Mine had no functionality at all, wouldn’t engage under any conditions. According to Clark’s, continued acceleration usually points to the servo unit, but testing the connectors should give you some more information. It seems like in most cases, it’s often the computers that have failed from what I’ve seen. The boards just don’t hold up well after 30 years.

[@notnilc20]

Thank you. Great video.

[@dalesdroid]

How does the actuator, part once you get the cover off? You have the solenoid and it looks like the card loose

[@NC944er]

This may provide some additional information - www.cruisecontrolrepair.com/servo

[@LezOU]

Great job as usual, is there a written (printer friendly) version of this somewhere ?

[@LezOU]

top plug 4-6 12V with ignition 2-8 12v with brake applied 3-8 12V, 0V with cruiser control cancel 5-8 0V, 12V with cruise control reset 6-8 0V, 12V with cruise control set/accel 4-7 12V, 0V with clutch operation bottom plug 1-2 30-40 ohms 4-7 2000-4000 ohms 4-8 2000-4000 ohms 5-6 20-30 ohms On my 944 S2; top plug 4-6 12V with ignition ->not ok 6-8 0V, 12V with cruise control set/accel - ok 4-7 12V, 0V with clutch operation - ok That gets me puzzled, since plug 4 and 6 are working in conjunction with 7-8, but not together ?

[@NC944er]

@@LezOU Hey! There’s a list in the manual you could print out - Workshop Manuals, Vol.1, Engine - p914-6info.net/944%20Manuals.html

[@LezOU]

@@NC944er thx, I found that I had it already and forgot to check. mine has the 2 plugs described which is an added bonus.

[@phil6012]

5:26 - Is that a typo? I see 2k-3k Ω on all the cars that I've checked.

[@NC944er]

@@phil6012 If it is a typo, it’s a typo in the factory workshop manual from where I pulled it. 😂 Check out Volume 1, Engine, Group 27, Page 24 (or page 235 if viewing the PDF version), Step 12 indicates that terminals 5 and 6 should read “every 20 - 30 ohm.” That said, I’ve also heard of people getting pretty varied readings from the servo tests while the unit is still operational, for whatever reason.

[@phil6012]

@@NC944er Thank you for the workshop details. I have the full set and was trying to find the cruise control section today, but I was in the electrical volumes. I've checked 3 cars (my 87 951, an 86 951 and an 86 944) trying to figure out pins 5 and 6 and they're all reading similar. However, none of them have working cruise control. Do you recall your readings? I applied MG Chemicals 8341 flux to the back of the controller board during my reflow process. Haven't taken it for a drive yet.

[@NC944er]

@@phil6012 Pins 5 and 6 on mine read right at 5 ohms, what that means I’m not quite sure, but the cruise operation is holding strong so far.

[@christopherbailey2313]

Greta video. Working on my 87 cruise right now. Chattering servo issue. Where you at in NC? I am over in Holly Ridge.

[@NC944er]

Nice! I lived in Wilmington for 12 years, but out by Burlington now. I’m finding there are quite a few 944s hidden away across NC. 😂

[@christopherbailey2313]

@@NC944er I LS swapped mine. Just did your electrical tests, and heat gun trick. Cruise worked, once. At least I know everything somewhat works. Going to scrape and reflow the card and see if that helps. Tracking down a spare module for good measure.

[@rrassoc]

Did you have your servo mounting brackets re-plated? I'm trying to figure out how to remove the rubber grommets, which are REALLY snug.

[@NC944er]

@@rrassoc I did have all the steel brackets replated in yellow zinc. The grommets will push out with some effort. If they are too far gone or damaged, new ones are available via part number: 999-702-133-40, but they are about $20 apiece.

[@user-mt5te8ec3j]

While removing the top plug, the top came off and all wires came out. Do you know which color wire goes to which number?

[@NC944er]

Sure, here you go... 1. Red/Black 2. Red/White 3. Brown/Yellow 4. Grey 5. Blue 6. Yellow 7. Brown/White 8. Brown

[@Aidan0802]

Alright, servo connector terminals 5 and 6 are only showing me 9 ohms instead of 20-30, what gives? Is this what’s causing the car to not have cruise control at all?

[@NC944er]

I’ve found those readings can be “slightly” out of specification and the cruise will still function, but that’s definitively something to investigate further… trace/check the wiring while looking for damaged insulation, oxidation on contacts, etc. Anecdotally from forum posts, it’s seems the computer fails more often than the servo motor. It may be worthwhile to pick up some used parts and swap them out to see if there’s any change or improvement.

[@Aidan0802]

@@NC944er yeah I picked up a used cruise control computer, did nothing. With my original cruise control computer though, it did work perfectly for about a few months and then it just stopped working all together one day Took out the servo and cleaned it, nothing. Just ordered a new used servo though. I do sometimes get a intermittent surging operation of the cruise control when I’m driving on the highway, I don’t know why this happens though

[@NC944er]

@@Aidan0802 Hmmm, surging acceleration generally points to the servo and failure to engage altogether is usually the computer. Mine was the same, worked perfectly one day and then nothing the next, ended up being the computer. Did the switch tests check out ok? Could at least rule that out. I suppose it’s possible that the replacement computer is faulty as well. Since you have a spare, it couldn’t hurt to heat gun it. I’ve also seen people bake the computers in a kitchen oven and get them going again. 😂 I haven’t tried that though.

[@Aidan0802]

@@NC944er yeah I mean sometimes after a half hour of driving, it’ll just surge. It usually just fails to engage at all. I just don’t understand why my original computer would go from working to not working at all. Even after a heat gun. First it stopped working, then used a heat gun, it worked, and then never worked shortly after that. Bought a used computer that was original and ig that one just surges intermittently, also used a heat gun on it and it didn’t really do anything The stalk tested good, everything works except for servo terminals 5 and 6 which is at 9 ohms instead of 20-30. The replacement computer could be faulty too but it doesn’t look like anything is faulty on it

[@NC944er]

@@Aidan0802 The computers are all the same, even through the 968. If you end up deciding to pick up another one, I’d try to get the latest production date you can find. Should be stamped on the outside. Maybe a better chance of it holding up that way, banking on improvements in manufacturing and less age on the materials.

[@johnrugal9599]

Wow ... Thats what I was looking for

[@NC944er]

Glad you found it useful! 👍🏼

[@johnrugal9599]

@@NC944er I am restoring a 1988 car. Its missing ABS cables and I am not sure how to put back together ABS system. Overview of ABS system can be another one of your project. Keep up the good work.

[@NC944er]

@@johnrugal9599 Did your car come with ABS as an option and then someone deleted it? My ‘88 didn’t come with ABS, it was available after ‘86, but didn’t come on every car.

[@johnrugal9599]

@@NC944er I believe it has wiring for the ABS system but someone decided to remove it. May be I need to look at the options codes again.

[@snoopymagikkarmannghia5116]

Je suis de Belgique et je vous dit BRAVO ;)

[@NC944er]

Thank you, I appreciate the feedback! 👍🏼

[@lesdmark]

That looks like a version of the same system Mercedes used on all of their cars from the same time period. The thing is that all German cars from this period are built from the Bosch/VDO parts bin so there are a lot of weird crossover parts between all the cars.

[@NC944er]

Yeah, I wouldn’t be surprised if it were shared across other platforms. I’ve found a number Audi logos on various parts around the car as well.

[@rossstoneman832]

Has that car ever even been started? It looks like brand new!!

[@NC944er]

HA! Believe it or not, I just passed 171k miles on it!

[@rossstoneman832]

@@NC944er that’s incredible!!

[@commotoed]

Ha ha, I removed all that stuff and even modified the switch stalk, my 944S is de-contented...for lightness!

[@NC944er]

Does the switch stalk now control something ultra cool like an ejection seat or missile launchers or anything?

[@ed_cetera]

Succinct commentary

[@sammiewilkinson4079]

ᑭᖇOᗰOᔕᗰ