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I am swapping cruise control into an '01 Legacy L / Brighton, and I need some help troubleshooting the completed install.

 

What I've done so far:

- Install cruise main switch, steering wheel controls, actuator and cruise computer

- Wire cruise actuator through firewall to cruise computer

- Wire cruise computer to all respective wires in the vehicle according to the wiring diagram (this was quite a procedure)

- Wired in new 4-wire brake and clutch pedal switches and confirmed it has continuity when no pedals are pressed

- Tested and verified all switches, bulbs, ignition power sources, etc

- Then I plugged in the cruise module and tried it out, and the light on the cruise control main switch will not come on when I press it (I'm assuming it means 'enable the cruise system').

- I have checked fuse 18 and 15, and backprobed all points from the switch and the bulbs to check that the module genuinely isn't responding, but is otherwise powered.

 

My issue is as follows:

 

The cruise enable switch on the dash does not light up when pressed. Bulb works, switch works, power goes to the cruise module, what else do I check??

 

UPDATE

The cruise module wasn't enabling because the sub-switch output to pin 10 of the cruise module was wired at connector B68 by wire-color and not by pin number. On my particular vehicle (Legacy Brighton L), the wire colors on the steering-wheel side of that harness are incorrect and/or mislabeled in either the vehicle or the wiring diagram. Doing this by pin number means that the cruise module now powers on, and the correct 12v signal is seen at the module when the set, resume and cancel buttons are operated, respectively. The issue now is that it will not set cruise, when driving over 40km/h - the switches do not do anything. I need to troubleshoot whether something is inhibiting the cruise system from setting, or whether it is trying to set the cruise, but the actuator is not working. Any ideas are welcome.

 

Please let me know what you guys think is the best next-step to take to get this working.

 

Some photos of the progress

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Edited by QB89Dragon
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If you haven't verified that all the power lines and ground that tie to the module, including the switch lead, are making good connection to the module then you need to do that. Are you sure that the system was working before you exchanged it?

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If you haven't verified that all the power lines and ground that tie to the module, including the switch lead, are making good connection to the module then you need to do that. Are you sure that the system was working before you exchanged it?

I have verified the power lines and ground. Though I have now got the cruise light to come on (the issue was the wire colors on the cruise control sub switch harness were not the same as the diagram). My issue now is that the system turns on, but you can't set a speed - i.e. it doesn't cruise. I've tested the sub switch wires, and they are good. However the one missing link is the B54 connector pin a11 - my car is MT, however the diagram indicates that it should be still connected to something (the neutral switch maybe?). I have no B54 connector that I can find under the dash, so I left the wire unconnected. Maybe this is inhibiting it?

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I have verified the power lines and ground. Though I have now got the cruise light to come on (the issue was the wire colors on the cruise control sub switch harness were not the same as the diagram). My issue now is that the system turns on, but you can't set a speed - i.e. it doesn't cruise. I've tested the sub switch wires, and they are good. However the one missing link is the B54 connector pin a11 - my car is MT, however the diagram indicates that it should be still connected to something (the neutral switch maybe?). I have no B54 connector that I can find under the dash, so I left the wire unconnected. Maybe this is inhibiting it?

Well, I might be wrong about the B54 connector thing as the (AT) is on the cruise module side of the wire, so it should not be connected to anything. I'm stuck on whatever is inhibiting it setting. Is there any way to troubleshoot this further?

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The wire from B54 is the speed signal. Do you have the green/black wire connected to your speed sensor?

Yes I do, I get a pulsating 4.7 volts on there, so that one is correct. The Black / Orange wire is not connected, also the White / Black (AT) on pin 4 is not connected. I'm driving at over 40km/h when attempting to set cruise and nothing is happening.

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The wire from B54 is the speed signal. Do you have the green/black wire connected to your speed sensor?

Also there is a black wire that terminates at pin 5 of B68 that isn't connected to anything. This may be something to do with the set resume cancel switch? Should it connect to something?

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Do you have 12v gettin to the sub switch? Do you get 12v on the two wires coming out of the black plug from the clock-spring when the switch is pressed? (Make sure the key is on)

 

 

Pin 4 WB wire. ST circuit from the ignition switch goes to the start contacts IIRC. That will only get a signal when the key is turned to the start position, but it may be necessary to "wake-up" the module. Not 100% sure on that though.

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Do you have 12v gettin to the sub switch? Do you get 12v on the two wires coming out of the black plug from the clock-spring when the switch is pressed? (Make sure the key is on)

 

 

Pin 4 WB wire. ST circuit from the ignition switch goes to the start contacts IIRC. That will only get a signal when the key is turned to the start position, but it may be necessary to "wake-up" the module. Not 100% sure on that though.

I get 12v going right to pins 9 and 10 on the circuit board of the cruise module when the cruise sub switch buttons are pressed, no issue with how its wired to my knowledge.

 

I've also tried connecting pin 4 WB to 12v, and the cruise still doesn't engage. I may try wiring a bulb to each of the motor outputs of the cruise module to know if it is commanding them to operate or not. That way I could rule out either the actuator or cruise module.

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Do you get a change of voltage on the clutch switch wires when you depress the clutch pedal?

I don't have the clutch switch yet, the wires are connected down there though. The circuit is continuous from pin 11 to pin 16 (brake and clutch switches) when the brake isn't applied.

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Does the actuator have a vacuum pump on it or does it use engine vacuum?

 

If you have a hand vacuum pump, make sure the actuator and the diaphragm hold vacuum.

This one either has an internal vacuum pump, or is purely servo driven. It does not have any external vacuum lines, or an external vacuum test port from what I can tell. It is part number R174737 https://www.google.ca/search?q=R174737&es_sm=91&source=lnms&tbm=isch&sa=X&ved=0CAgQ_AUoAmoVChMIz7SVrYepxwIV04uSCh3elwYN&biw=1920&bih=1036#imgrc=1NYf4zr8-n8KtM%3A

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Ok. Do you have 12v reaching the actuator on pin 4 when the main switch is on?

 

FSM test procedure for the actuator is to measure resistance on pins 1 to 4, 2 to 4, and 5 to 4, should be around 5 ohms.

Pin 3 to 6 should be about 39 ohms. If any out of pec then the actuator is bad.

 

The cruise module grounds pins 1, 2, and 5 on the actuator to set, increase, or decrease speed, but voltage can only be tested when driving.

 

You should be able to test the actuator function by grounding those pins while the main switch is on.

Edited by Fairtax4me
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Ok. Do you have 12v reaching the actuator on pin 4 when the main switch is on?

 

FSM test procedure for the actuator is to measure resistance on pins 1 to 4, 2 to 4, and 5 to 4, should be around 5 ohms.

Pin 3 to 6 should be about 39 ohms. If any out of pec then the actuator is bad.

 

The cruise module grounds pins 1, 2, and 5 on the actuator to set, increase, or decrease speed, but voltage can only be tested when driving.

 

You should be able to test the actuator function by grounding those pins while the main switch is on.

 

I have 12v hitting pin 4 when the switch is on.

I tried testing the actuator function by grounding those pins, however it didn't work out so great. The relay clicked off on the module, and now the thing clicks on but the main switch light doesn't work. I think something might have been damaged by that test.

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Check to see if you have close to 12 volts on pin 1 of the CC module while the switch light is supposed to be turned ON. If you do have voltage there then perhaps there is a problem with the module though I'm not sure how that would happen unless a wrong pin was grounded during the test. Pin 1 of the module should be close to ground potential to turn on the switch light.

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I have 12v hitting pin 4 when the switch is on.

I tried testing the actuator function by grounding those pins, however it didn't work out so great. The relay clicked off on the module, and now the thing clicks on but the main switch light doesn't work. I think something might have been damaged by that test.

Did you ground any pins other than 1,2, or 5?

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  • 2 weeks later...

Did you ground any pins other than 1,2, or 5?

The module came back to life after that event 24 hours later (maybe bad caps or something?) but it works the same and I now have a second cruise module that has the same results.

 

No, I didn't ground any other pins when I initially did the test. I have double checked and tried the test again with the same results except the system comes back to life again instantly after turning the key off and on.

 

When grounding the pins, the relay just clicks and the system shuts off. I'm going to test all wires to the cruise module and try and get a proper reading on the resistances across the different motors.

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Alright, if the module is reacting oddly then it must not be as cut and dry as power in one pin and ground through the three others. Luckily it must have a circuit breaker or something in it to protect the module. Probably in case of a short circuit/cut/chewed wires under the hood.

 

I'll have to see if I can find a schematic for what's going on in the actuator. Wire diagrams don't tell the whole story.

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Alright, if the module is reacting oddly then it must not be as cut and dry as power in one pin and ground through the three others. Luckily it must have a circuit breaker or something in it to protect the module. Probably in case of a short circuit/cut/chewed wires under the hood.

 

I'll have to see if I can find a schematic for what's going on in the actuator. Wire diagrams don't tell the whole story.

Thanks. Let me know if you find anything. I'm going to keep rechecking the wiring to the engine bay and swap out the cruise actuator for another unit I have here.

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I got it working!!

 

Turned out there were two things wrong,

 

1. I had a bad cruise actuator unit, it had jammed gears that had stripped out, hence why it was clicking off the relay when testing it.

 

2. I had a bad tap connector onto the VSS (Vehicle Speed Sensor) wire, so it wasn't sensing the speed.

 

I tested it with all four wheels in the air to finally get it figured out, so far it works great and is a joy to use on the highway.

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