cruise control (SOLVED)

Topic: cruise control (SOLVED) (Read 9407 times) previous topic - next topic

cruise control (SOLVED)

December 30, 2007, 11:50:36 AM

Well, i have a small list of things to repair on my 20th and the cruise being inop was on the list.
Yesterday i pulled pulled the car in to begin the dreaded task of trobleshooting.

gazing at the evtm..........

Key on engine off, I find power going to the cruise control box on the light blue wire, I also find power going to the cruise control box on the light green wire when the brake is applied.

I swap out cruise control units (located upper left from brake pedal). No fix.

Back to the evtm. Lets see what my steering wheel switches are doing. Remove column covers and locate the small harness that leads up to the steeriing wheel slip rings and ultimatly to the switches consisting of a blue, purple and black wire.
-Unplug the small harness and test on the sterring wheel side for conitinuity.
-hook meter up to the black and light blue
-press the OFF button and my meter beeps so this tells me i have a good path from the blue wire, through the slip ring, through the OFF side of the switch and back to the black wire. (this tells me that so far my slip rings are working).

-Hook meter up to the black and the purple wire
-Press the ON button and the meter does not BEEP>>PROBLEM
next, leave red meter lead hooked to purple wire and remove the black meter lead
pop off horn button and locate the slip ring connector at your six O'clock.
touch your black meter lead to the purple wire on the slip ring connector.
Yes, i have continuity on the PURPLE wire from the the ON side of the switch down through the slip rings and finally to the connector in the column.
Repeat for the black wire. Hook red meter lead up to the black wire on the column connector. Touch the black wire up at the slip ring connector at your six oclock under the horn button. Yes, i have continuity. I have a known good path from the column harness and through the slip rings even with i wiggle test the steering wheel.

Remove covers on the rear of the steering wheel switches.
locate wiring harness
get pissed because i cant extract the wiring from the slip ring connector
cut wires in the switch compartment
bring switch to work bench and continuity test from the black to the purple and actuate switch.
NO BEEP
SWITCH IS DEFECTIVE!!!!!!!!!!!!!!

Take switch apart by pressing out the two rivits
study its design and lift up the long metal contact
notice the red wire metal tab is worn preventing contact

To be continued,,,,,,,,,,,, Attempt to repair switch today.

I expect my cruise to be operational soon.

cruise control (SOLVED)

Reply #1 – December 31, 2007, 09:05:31 AM

When you going to realize you don’t ask for advice you give it

Between you and Thunderchicken thank god I knows you guys for my electrical frustration is your advice

cruise control (SOLVED)

Reply #2 – December 31, 2007, 01:57:20 PM

well, dont jump too soon,,,,,,,, NO FIX YET

I am confussed on the on and off switch. Apparently i am not suppose to have continuity from black to purple when the on is depressed. Instead i am suppose to have continuity from the purple to blue.

Moving along i remove the RESUME/SET ACCELL/COAST SWITCH

This switch has only two wires, the same black and blue from the on and off switch.
I press various buttons and have no continuity anywhere.
I take the switch apart and find a RESISTOR BANK per the shop manual pages i posted a while back.
I bend up the little metal tab back up so the switch can make contact.
Suddenly i have readings per the shop manual 125ohms, 680ohms, 2.3k ohms all showing the coast, resume and set accel is working properly.

Install both switches and NO FIX.

MOVING ALONG TO THE SERVO TEST.
I am failing the servo test when i momentarily touch circuit 145 to ground. Engine does not raise in rpm. I do hear a noise near the servo but i dont get the results in the shop manual.

If anyone has any ideas let me know. The Cruise shop manual pages are posted here i think in electrical tech.

cruise control (SOLVED)

Reply #3 – December 31, 2007, 07:33:02 PM

ok,, does anyone have any experience working on the cruise servo assembly?
When i apply a momentary ground to the servo on circuit 145, i hear the servo doing something.
My first thoughts are the servo is binding up.

Does anyone have a pic of the servo asembly? Im thinking of disconnecting the cruise cable and working the cable vigerously back and forth to loosen something up. Also, im not sure how its internally designed.

My only thing left to do here is get to the servo.

Lucky me

Im really beginning to think common sense here.,,,,, the servo is binding up because of the lack of use. My next trick is to spray wd40 down the vac tube leading to the servo. Hopefully some of that will drain down to a moving part. I know that the wd will get sucked back into the vac system and that really wont hurt anything. It will actually help lube up the internals of my vac actuated devices.

Who is it here who also has a 20th with an INOP cruise?

anyway,, any help would be appreciated cause this is going to be a challenge. I need to redirect my attention to control arm bushings next weekend since Napa finally got the right ones shipped. The wife is worried about the poping on the front end.

cruise control (SOLVED)

Reply #4 – December 31, 2007, 11:56:31 PM

Does the horn work?

cruise control (SOLVED)

Reply #5 – January 01, 2008, 04:12:19 AM

yes, horn works.

cruise control (SOLVED)

Reply #6 – January 01, 2008, 10:47:24 AM

Saw this yesterday decided to thoroughly read through it. I'm the one with dead cruise.

I did some testing with the contact rings I think either from your massive DIY tutorial or from the evtm. Don't really remember what happened it was early this summer. I used ohm readings, didn't have the beeper turned on on my multimeter but I did get readings I was just going by the guidelines and they weren't quite within spec but there was obviously a connection.

I got the SAME result if you recall when I did the thing to manually override everything and jump the servo, same deal no increase in rpm but I heard a click from the servo with the engine off, and if I broke the connection then shut the engine off I heard what sounded like a hissing/air rushing noise coming from the servo.

Good point on "lack of use". Though that doesn't really apply in my case I don't think because my mom says my dad used it all the time when he bought the car and it suddenly quit I think within 1 year. No idea of its use by the previous two owners or how frequently dad used it.

I was thinking of just finding a replacement servo. I cant help but wonder if it's still somehow a similar situation to yours (if your theory is correct). If you decide to take it apart I'll be watchin'! :D Then maybe I'll try mine.

cruise control (SOLVED)

Reply #7 – January 01, 2008, 12:11:03 PM

ahh
new found hope for us:hick: Im not sure why i didnt notice this earlier.

My plans to test the servo per the below drawing............

KEY OFF, ENGINE OFF TEST

step 1
-unhook the right hand connector C3003
-connect ohmeter to wires brown/light green and pink/light blue.
-meter should read about 50k ohms

step 2
-connect ohm meter to the yellow red and brown light green
-note your resistance reading
-push in the gas pedal and the resistance should smoothly change
-slowly release gas pedal and resistance should smoothly change

-connect ohm meter to the yellow/red and pink/light blue
-note your resistance reading
-push in the gas pedal and the resistance should smoothly change
-slowly release gas pedal and resistance should smoothly change
**the above two steps should be identical but opposite if i am correct.
**the above steps verified the cable to the servo moves the variable resistor on the servo and desired results proof test.

step 4
-Apply vac presure to servo vac feed and observe it holds vac

step 5
-connect ohm meter to the orange/yellow and white/pink wires
-check for a resistance of 60-190 ohms
-slowly apply vac presure to the servo vac line
-observe the resistance reading changes smoothly
-ASSUMPTION-gently press on brake pedal and vac presure will bleed off at the dump valve on brake pedal.
-observe the resistance changes smoothly

-connect ohm meter to the orange/yellow and gray/black wires
-check for a resistance of 40-125 ohms
-slowly apply vac presure to the servo vac line
-observe the resistance reading changes smoothly
-ASSUMPTION-gently press on brake pedal and vac presure will bleed off at the dump valve on brake pedal.
-observe the resistance changes smoothly

lets see if this helps any........to be continued

cruise control (SOLVED)

Reply #8 – January 01, 2008, 03:27:13 PM

Re step 5.
I don't think the resistance value of the solenoids in the modulator valve are going to change with vacuum.

Test proceedure for the servo from the 84 shop manual:

With connector 3003 disconnected, do the resistance checks of the solenoid coils.

With connector 3003 still disconnected start the engine.
Connect the O/Y wire #144 to battery positive.
Connect the W/PK wire #146 to ground.
Momentarily touch the GR/BK wire #145 to ground.
The servo throttle arm should pull in and the engine speed should increase. The arm should hold in that position or slowly release.
When the W/PK wire #146 is removed from ground the servo should release.

Now I am going to read your DIY and see what it says.

Yes this agrees with what you posted from your shop manual.

cruise control (SOLVED)

Reply #9 – January 01, 2008, 04:58:23 PM

After rereading the thread, it looks like you already did the servo test.
Of course the test assumes you have vacuum to the modulator valve and the brake dump valve is closed.

Is it possible that the servo cable to the throttle linkage has disconnected from the servo actuator?

You have to remove the wheel and the inner fender splash shield to check that.

cruise control (SOLVED)

Reply #10 – January 01, 2008, 06:37:55 PM

Quote from: softtouch;195345

Is it possible that the servo cable to the throttle linkage has disconnected from the servo actuator?

You have to remove the wheel and the inner fender splash shield to check that.

my god man, you are soooooooo on the the mark!!!

SO,,, Lets both feel like idiots for a moment,,ok?
Is that,, or ,, Is that not the schematic symbol for a variable center tap resistor on wires 147-149?

It was my assumption that i could verify the throttle cable was connected by placing my ohm meter from circuit 148 to 147. When i connnected my meter up to 148 and 147, the resistance was about half (25k ohms) which i expected. I moved my gas pedal and the resistance did not change.

I was thinking right then and there i just found my problem,, my cable came unhooked!!!!!

I connected the ohm meter on 148 to 149 and moved my gas pedal. Still,,, no resistance change!!

I run out to the white cougar with working cruise control. I perform the same checks and the results were the same,,, The resistance does not change!!!!!

I am pissed......... :mad: :mad: :mad:

I thought for sure my tests would yield the same results as if you were reading a TPS,, its just a center tap resistor for christ sakes!!

SO here is what i am thinking,,,,,, maybe i need to pull a vac on the main servo vac line in order to make the resistance change. Im going back out to the garage to check that but its too dark and cold out side to verify my readings against the white cougar to proof test.
Im thinking that even if i move the pedal,, the cable is just sliding inside free inside the servo cause its not strong enough to over come the tension.

Basically, i think im working this issue backwards. I need to pull vac and then watch the resistance changes from 147 to 148 and then from 149 to 148.

make sense?

Also,, if i pull a vac on the servo assembly, the throttle linkage should also be pulled. If i see a resistance change on the meter but the throttle linkage does not pull at the throttle body, I will then know for a fact, the cable came disconnected.

cruise control (SOLVED)

Reply #11 – January 01, 2008, 07:05:43 PM

Oh my God F this. LOL but seriously I love how there's about 1.3 million different things it could be. I'm seriously reading this all and shaking my head.

Quote from: jcassity

but its too dark and cold out side to verify my readings against the white cougar to proof test

SHEESH, I cannot count how many times I've wanted to start a rather involved project on my car during the winter and then remembered oh wait its about 45 degrees out there I gotta turn on the elec. heater, open the basp00get door to let the warm air come up and wait like a half hour for it to come up like 10 degrees and even then I'm not 100% comfortable.

cruise control (SOLVED)

Reply #12 – January 01, 2008, 07:40:17 PM

nope,,
pulling a vac on the servo does not change the resistance nor does the cable pull in at the throttle body.

I did not verify against the other coug yet.

perhaps someone can help out here.

cruise control (SOLVED)

Reply #13 – January 01, 2008, 08:17:58 PM

You have the right idea about checking the center tap resister to detect servo movement.

In order for vacuum to move the servo motor (this is a vacuum motor not an electric motor) you need to energize the solenoids on the modulator valve. Just like you did when you did the servo test.

When energized, the top solenoid opens the vacuum valve and the bottom solenoid closes the vent valve. So you need them both energized to apply vacuum to the servo.

I suspect that by design the servo cable cannot push the servo motor when you step on the gas.

cruise control (SOLVED)

Reply #14 – January 01, 2008, 11:41:18 PM

ahh,, i see now.

I sure couldnt tell all that by looking at the illustrated parts in the shop manual or the evtm but ill take your word.

so my plans are to **JUST** energize the modulator valve via circuits 144 and 146.

I will not do the momentary "touch" of 145 to ground. Instead,, i will pull a vac on the servo hose and check the resistance readings do vary. I should also be able to see the throttle linkage being pulled in as well ,,(that is if the cable is connected to the servo)

am I tracking you correctly?