Author Topic: Cruise Control Retrofit Failure... (Read 8330 times)

AcSchnitzer318is · « **on:** February 22, 2011, 04:04:31 PM »

Well, followed the directions on the DIY and installed cruise today. Of course I go to try it out and it does not function.

My question is where should I start troubleshooting? I don't know if everything worked prior to install as it came out of a yard car. I'm guessing the wiring is good as it looked to be in good shape.

Is there a way to test the actuator without just replacing with a known good one? I can do that but would rather not tear apart my convertible's working cruise to start swapping parts.

Thanks for any suggestions.

DesktopDave · « **Reply #1 on:** February 22, 2011, 04:17:37 PM »

Did it ever work? I'm not trying to ask dumb questions, but are you sure you used the correct M20 actuator? The e36 one won't work from what I've heard.

Did you crimp the main power loom onto the brake wires? Mine quit working recently too. It took me a while to figure out why. The brake light switch was cracked internally and not turning on the brake lights. No power to the cruise unit AND no brake lights as a bonus. I felt like a bonehead for not noticing the brake lights failing.

Second time was more interesting. The cruise unit just stopped working on the highway. I found that the actuator strap had pulled off the cable clip inside the actuator neck. That's an annoying repair to perform at a rest stop with a 40mph wind at 40 degF.

monko141 · « **Reply #2 on:** February 22, 2011, 08:19:08 PM »

Check to see if the clutch pedal cut off switch is adjusted properly.

AcSchnitzer318is · « **Reply #3 on:** February 23, 2011, 07:02:57 AM »

^I was under the impression you should still have functioning cruise without the clutch switch? At least that's what it sounded like according to the DIY.

I did crimp onto the brake circuit though only one of the wires matched. The green/red one matched and the purple/white one did not. Should I have connected that one elsewhere.

I guess first place to start would be to check whether or not the computer is getting 12v... then check the actuator. I did use an m20 one with an e36 actuator cable...

monko141 · « **Reply #4 on:** February 23, 2011, 08:00:44 AM »

Purple/white needs to be connected to "Accessory" power. I picked it up off the radio circuit. Green/red needs to be connected to the "load" side of the brake light switch.

DesktopDave · « **Reply #5 on:** February 23, 2011, 01:51:12 PM »

The cruise plug needs to be shorted if you don't have a switch IIRC. Auto tranny cars have a small plug with a wire connecting both terminals. It completes the circuit by shorting out the clutch plug.

AcSchnitzer318is · « **Reply #6 on:** February 23, 2011, 02:21:51 PM »

^Thanks for those tips guys... will try it out.

Neither of those points are mentioned in the DIY page... I'll post an update on that when I am done and have everything working as it should.

AcSchnitzer318is · « **Reply #7 on:** February 24, 2011, 12:59:19 PM »

Ok no luck... I tested the purple/white wire and it is indeed getting switched +12v even though it is tied into the brake switch's purple/green wire. I went ahead and shorted the clutch switch wires as well... they were the same color so it made sense anyway.

So let's recap, I have the speedo wire hooked up to A on the green plug of the cluster. I have the green/red wire of the cruise harness tied to the green/red of the brake switch, and I have the purple/white wire tied into the purple/green wire on the brake switch (verified switched 12v). Of course all harnesses and plugs are attached (stalk, computer, actuator). Am I missing something or is one of my components dead?

Personally i am leaning towards one of the components being kaput. I asked my buddy at the shop I work at (BMW idie shop) and he says it is very common for the cruise computers to take a dump.

Thoughts?

DesktopDave · « **Reply #8 on:** February 24, 2011, 05:46:41 PM »

Sounds like you have your bases covered. That's a hard system to test. I don't know the pinout...and it's nearly impossible to test that thing in action with the car heading down the road.

I'd be tempted to get an assistant to test the actuator connector in action...but that's be unsafe and you'd need some really long probes. There has to be an easier way. A signal generator and a 12vdc power supply might do the trick.

AcSchnitzer318is · « **Reply #9 on:** February 25, 2011, 01:35:39 AM »

Signal generator is the only way I could think of without tearing into the working car's cruise. Since I didn't want to try and locate one I tore into the other car a bit.

I tested the suspect computer in the convertible (working cruise) and it was good. Cruise worked perfectly. I also tested the wiring at the computer to verify I was getting the same sorts of results in both cars. I was.

So tomorrow... I am going to test the actuator, and then the switch. I am going in order of work needed to test... sooooo we'll see how that goes. Personally I think it's the actuator even though they generally never go bad (so I'm told).

DesktopDave · « **Reply #10 on:** February 25, 2011, 07:14:46 AM »

It's a stepper motor in a gearbox. Lots to go wrong, though they've been OK in my experience too. BTW, if you figure out how to reassemble them with the proper preload, let me know. I pulled one apart last year and it's still apart. Never did get it working again.

AcSchnitzer318is · « **Reply #11 on:** February 25, 2011, 04:48:00 PM »

Ok... tested the computer, actuator, and stalk in the other car and everything is good. I wonder if there is a break in the harness somewhere? Going to pull the harnesses and check for continuity from one end to the other.

I doubt the speed sensor plug on the back of the cluster could be the problem, but with my luck that's what it will turn out to be.

AcSchnitzer318is · « **Reply #12 on:** March 01, 2011, 06:13:18 PM »

Ok, I am actually getting pretty damn frustrated now...

Tested all the components (except wire harness) individually in another car and they all worked fine. Put everything back into the 318is and nothing. I am going over the wiring diagrams now and can not figure it out.

I have my green/red wire on the load side of the brake switch which is the purple/green wire and NOT the green/red wire as in the write up. I am getting +12v on the cruise harness' green/red wire... so if I connect it to the green/red wire on the brake switch my brake lights are always on of course... just like pressing the brakes completes the circuit. Is that normal to have +12v on that green/red wire?

Clutch switch is shorted with a wire going between the two green/red wires.

My violet/white wire is now on switched +12v somewhere other than from the brake switch... I think I used one of the wires on the ignition switch.

I have a 4000 mile road trip coming up and really want this functioning... any help is appreciated. I can't believe I am having this kind of difficulty adding what looks like a stupid simple system.

jakeb · « **Reply #13 on:** March 01, 2011, 09:15:12 PM »

Not sure which walk through you used but here is what I did when I did it with my last 318.

This thread, http://www.m42club.com/forums/showpost.php?p=6340&postcount=53

Pictures.... http://www.theguestroom.net/car/318cruise/

You need:

**full e30 cruise setup (wires, computer, stalk, actuator)
**e36 actuator bracket and the cable that goes from the actuator to the TB
**part number, 62 11 1 372 218, real oem calls it a plug housing....what it is, is a green plug that connects to the back of the cluster, it has some long stiff wires that push into little holes in the cluster and then the "plug housing" has a spot to plug the cruise harness into
**M5 x 20mm screw (this is a replacement for the lower screw that holds the wiper stalk to the column and then allows the cruise stalk to be held in place)
**wire taps (or something to do their job)
**2 conductor plug

You Do:

In the Engine Compartment:

Replace the actuator cable (goes from the actuator to the TB) with the cable that you pulled from the e36. To do this there is a clip you push down and then you can pull the cable out and unclip it.

Mount the actuator using the e36 bracket on the AFM mount.

There is a large rubber grommet that has all the other wires going from the engine compartment to the cabin and you can push the acuator wiring through that.

Inside the Car:

You have to remove the cluster, lower panels, steering wheel, etc etc. I used the OBC walk through to get it all off. I also installed the OBC at the same time.

Fish the cruise harness from the driver’s side to the passenger side, behind the radio, etc...there is a blue connector that connects to the cruise computer...same type as on the OBC and back of the cluster. The cruise computer is supposed to be installed with a special bracket...which I have. But I couldn't get it to fit in right. So I just set the cruise computer above the glove compartment and surrounded it with foam.

Install the "plug housing" in the back of the cluster...just slide it in...can't really install it wrong. Plug the cruise harness into the "plug housing" It goes into the middle plug..labeled with the letter "A"

Fish the rest of the harness around the left side of the cluster...I tie wrapped it up with the existing harness and brought it down under the column.

Mount the cruise stalk under the wiper stalk. There are two plastic bosses on the cruise stalk and they fit right into the column. Then the lower screw (replace with M5x20mm) holds them all together.

Plug the cruise stalk into the cruise harness. Tie wrap if you please.

There is a ground connection on the cruise harness....single squareish plug. I did not know where this was supposed to plug in, so I cut it off and crimped on a ring terminal and found a something to ground it on. I used the mount for the knee pas thingy on the left hand side.

Then there is a 2 wire plug...one blue/white wire and one green/brown (I will double check the colors. ) This normally plugs into a junction block, which our cars have but it is missing the actual pins where it would make contact. So you will need to cut this off...get a different 2 wire connector and splice it into the brake light switch. The colors match(makes it easier) This spot is where the cruise system gets its power.

Connect the actuator cable to the cruise harness.

You will have one wire with a spade connection that you don't need...it is for auto cars only. Just tape it back to the harness.

I didn't install the clutch switch just yet but I will soon. It just plugs into the harness....white connector.

And that’s it!

Put all the panels back on...or try it first (what I did)

I did take some pictures as I went along...not a lot as my batteries were dead the first day. And I was kind of excited to get it all in. But I think I got enough to explain it a little better...along with this written explanation.

In addition to having this and the OBC...I was "cruising" at 50mph and reset the OBC MPG mode and it said I was getting 50mpg... It was a very flat spot, who knows if I was really getting 50...or not but it was cool none the less

DesktopDave · « **Reply #14 on:** March 01, 2011, 09:23:35 PM »

I don't think the wiring is right on the brake. The wires match on my cruise to the brake switch. I'm thinking it can't be turned on unless you have the polarity correct. You've really covered all the bases though. I'd be willing to bet that the cruise can plug into any one of the cluster sockets, they're probably all the same signal intended for various optional sensors.

+1 on the single ground wire... I don't remember you mentioning it. It's a single brown (or brown/yellow?) wire that goes into a single white connector. I pulled mine with the little eyelet terminal intact & used that to ground it at the firewall main ground stud.

There must be some differences between the years. My harness has brown wires off the clutch switch. The brake wires were the same color as the cruise power switch, so I spliced them right in. I also noted that early cars had a different cruise stalk connector, but that can't be your trouble because they physically won't fit into a late model harness.