Ad Radar
12 Last
Item Posts    Sort Order

C4 Cruse Control not working

 
Jamesvette
I love my Chevy Chevette!
Posts: 8
Joined: 04/13
Posted: 04/25/13 11:35 AM

I have an 84 with the 4+3 transmission.  A couple of years ago the cruse stopped working. I replaced the instrument cluster due to a broken segment in the fall, and I would like to get the cruse working again. I have all of the voltages at the turn signal stalk and pedal switches. I can activate the 2 sol valves by applying voltage to pins A,C and E,C to have the servo draw and hold a vacuum, manually and with the engine running. I have 8.1 volts between B and D on the connector, and I have 22.5 ohms at the coil B,D pins on the servo.  The servo coils do not energize, click, when the power, 8 volts, is applied to the servo, by turning on the cruse switch.  Any body have any suggestions to what other tests I can perform, or what the problem might be?

Read more: http://www.vetteweb.com/tech/vemp_1007_c4_cruise_control_repair/viewall.html#ixzz2RV6VgY2N  

Post Reply
waynep712222
V-6 Camaros rule!
Posts: 35
Joined: 04/13
Posted: 04/25/13 02:44 PM

do you have this diagram

84 C4 Cruise Control Zps35d6195c  

Post Reply
waynep712222
V-6 Camaros rule!
Posts: 35
Joined: 04/13
Posted: 04/25/13 06:39 PM

you are also going to need to print this and study it.. as the speed sensor signals from the transmission come to the speedometer FIRST.. then to the ECM and probably the cruise control..


ahh.. i see in the diagram above.. the upper right corner of the big box in the middle.. that this is part of the speedometer cluster...   be sure to shift to the right..

C4cluster 32Pin  

Post Reply
waynep712222
V-6 Camaros rule!
Posts: 35
Joined: 04/13
Posted: 04/25/13 07:38 PM

I have all of the voltages at the turn signal stalk and pedal switches. I can activate the 2 sol valves by applying voltage to

pins A,C    pin A is the dark green wire.. and this gets pulsed by the Controller to dump vacuum from the servo.

and

E,C to have the servo draw and hold a vacuum, manually and with the engine running. Pin E is the light green wire, this gets pulsed by the controller to let more vacuum in.. ..

unless you are in override at the electronic controls either in the HVAC control board like is done on caddys.. or with an advanced scan tool.. you are not likely to find  any voltage there.


I have 8.1 volts between B and D on the connector, and I have 22.5 ohms at the coil B,D pins on the servo.  The servo coils do not energize, click, when the power, 8 volts, is applied to the servo, by turning on the cruse switch.

PINS B and D are hooked up to the servo position sensor.. if you manually move the servo in and out .. this should change.... lets the controller know how much the servo is moving so it can think ahead and respond with the vacuum control valves..


i am taking that the Speedometer actually works properly?  reads miles per hours...

you can jack up the rear end and spin the wheels to check this..

key on.. you should get a pulsed voltage when measured ...


since you have a 4+3 car.. i would want to check or replace the switches on the brake pedal and the clutch pedal... upper left corner of the wiring diagram...

lets talk about that circuit...

when the Key is ON  and the cruise switch turned ON you should have power at cluster connector C7.. this is direct thru the cruise switch...

continuing on a different branch of that circuit..   with your foot off the brake and off the clutch pedal .. you should have battery voltage .. the same as on pin C7 but this time on pin C12

more than likely your issue is going to be with the brake cruise control or the clutch cruise control...  i seem to recall that a lOT of people have  had to bypass the clutch interlock switch...

i don't have a C4. to look under the dash... but i wonder if the clutch interlock switch has 4 wires  or its 2 separate switches...   please verify pin C12 power... until you step on the brake pedal.. then it should come back.. when you lift your foot off..   and then when you depress the clutch pedal..  and when you release .. the power should come back...

why am i fixated on these..   because i have had them fail on other cars...

without the voltage passing thru that completed circuit.. the servo will NEVER get power to close the vent valve...,.. what... yep.. no power to the green wire.. the cruise control servo is going to just dump any vacuum to the atmosphere...


please DO NOT BYPASS ANY OF THESE SWITCHES..


on the new years eve of  2000   the city was going to light the hollywood sign with hollywood studio effects... there were a LOT of people watching it..  a small truck came roaring down the hollywood freeway..  up the offramp and right thru a crowd of people in the crosswalk.. striking a brand new toyota land cruiser.. it bounced off that and went sideways were it rolled over... landing back on its wheels about 100 feet down from the land cruiser but the throttle was stuck wide open...  i could see skid marks where the first tire touched the pavement. then the other.. they made a perfect ribbon loop as it burned rubber to stop and then burned rubber taking off again..  it crashed part way thru the door of the midas there..  the driver got out.  when the paramedics were finished checking him.. i ask what happened.. he said he had just purchased this truck a few days before.. and he was playing with the cruise control.. and it stuck on at full throttle..  i the rear brakes were still glowing when i got to it..  the fronts were smoldering as the engine could not be overpowered by the braking system..  the owner did not know to shut off the key or push it into neutral..   i never did hear back from the LAPD.. who impounded the truck..  as i talked to the impound officer and mentioned that the cruise control brake switches needed to be checked..  to see if the previous owner had tampered with them.. he just did not seem to care..   i mentioned to the local TV station camera operator  that this might be the first instance of the Y2K computer failures..   being that it was 12:00 midnight when it happened..


say.. while i am runaways.. recall the toyota prius owner who had a runaway down near san diego.. and he had a corvette jacket on...  a local reporter went down and did a broadcast from the toyota dealer where that car had been taken to for an exam by toyota and NHTSA techs..  he announced that they had found many depressions of the brake pedal and many depressions of the throttle pedal.. so it must be drivers fault..  i called the station and ask them to send him back in.. and ask what the drive by wire throttle body position sensor voltages were was during these multiple depressions and releases of both pedals...  since i ask that.. i have not heard a single runaway toyota announced on TV...

a friend at a ford dealer with a NON FORD badged product was sitting there and just going from idle to the rev limiter and back to idle.. again and again..   the whole shop of techs was standing there while the lead tech was on the phone with that brands tech department.. that guy said its impossible for that to happen.. the ford tech held the phone out and yelled.. he does not believe me..    the group of probably 20 techs yelled.. its doing it.. and it was .. in the background they could hear the engine going from idle to rev limiter again and again.. funny... a flat bed showed up in less than an hour and took that car away..  

Post Reply
waynep712222
V-6 Camaros rule!
Posts: 35
Joined: 04/13
Posted: 04/25/13 08:15 PM

21 25524844 * SWITCH, S/LP (M.T. EXC CR/CONT)(1984-86)(ACDelco #D889) * 1

21 25524845 * SWITCH, S/LP (CR/CONT)(1984-86)(ACDelco #D850A) * 1

21 25524848 * SWITCH, S/LP (A.T. EXC CR/CONT)(1984-86)(ACDelco #D851A) * 1

22 1645516 * VALVE, CR/CONT VAC & TRANS CONV REL(ACDelco #212-346) * 1

24 10075405 * RETAINER, CR/CONT VAC REL VLV (1984-85) * 1

24 22534155 * RETAINER, S/LP SW(ACDelco #22534155)

the switch item #22... delco 212-346 is shown for both the brake and clutch pedal  on manual transmission cars..    

Ac212346 1


this is an SW3028 at autozone or from wells


plunger depressed.. contacts closed..  

plunger extended.. contacts open...  vents when plunger is extended.. pedal depressed..

the vacuum section of these switches is shown at the lower right corner of the diagram..

the electrical portion of these switches is shown at the above left corner of the diagram..

if these switches are NOT available... take them out.. on a big towel.. you can disassemble them carefully..   the contacts inside are silver and you MIGHT be able to burnish them with the tip of a screwdriver to restore contact continuity..  

Post Reply
waynep712222
V-6 Camaros rule!
Posts: 35
Joined: 04/13
Posted: 04/25/13 08:21 PM

i bet you did not expect this much help.. .  

Post Reply
Jamesvette
I love my Chevy Chevette!
Posts: 8
Joined: 04/13
Posted: 04/26/13 04:50 AM

Thanks for all of this really good info. The speedo works correctly.  I have cheated the brake and clutch switches to insure that they are not the problem, but they did read good, and I have 12V at the gry/blk wire after the clutch switch. I will however reconnect them before returning the car to the road.

I will check the servo position sensor for changed in reading when the diaphragm is moved.  

Thanks again
James  

Post Reply
Jamesvette
I love my Chevy Chevette!
Posts: 8
Joined: 04/13
Posted: 04/26/13 10:25 AM

Well it looks like the servo is the problem after all.  When I move the throttle part of the diaphragm the resistance of the servo position sensor, pins B,D doesn't change.  I will order a servo and go from there.

I'll let you know of the final result.

Thanks again  

Post Reply
waynep712222
V-6 Camaros rule!
Posts: 35
Joined: 04/13
Posted: 04/26/13 10:59 AM

i hope that you get this...


please apply vacuum to the servo with the cable at the throttle body disconnected so you don't rev the engine ... this substitutes the controller and allows you to get an accurate test on the resistance..


or attempt the same test on a junk yard part.. or three... that servo style was used on many years of GM cars.. with only differences being the length of the cable. .


i don't have one of those to VERIFY with a bench test...

i can probably get my hands on one over the weekend... won't be a C4 version. but a GM version..  

Post Reply
Jamesvette
I love my Chevy Chevette!
Posts: 8
Joined: 04/13
Posted: 04/27/13 07:44 AM

My test consists of applying 12v to pins A and E, while grounding pin D.  This energizes both solenoids.  Next I used my vacuum pump to draw the diaphragm in.  The servo holds the vacuum, but the resistance of the coil at B,D doesn't change staying at a constant 22 ohms.  I am pretty sure that this is the problem.  If you do have a chance to test another servo, I would appreciate it.  I don't need to order the new servo today.  It can wait till Monday.

Thanks
James  

Post Reply
Jamesvette
I love my Chevy Chevette!
Posts: 8
Joined: 04/13
Posted: 04/27/13 07:47 AM

Sorry, that's pin C for the ground, not pin D.  

Post Reply
waynep712222
V-6 Camaros rule!
Posts: 35
Joined: 04/13
Posted: 04/27/13 12:42 PM

my junkyard run got canceled for today..


if the diaphragm/servo pulled in.. and the resistance did not change... then its probably the servo

edit..

sundays junk yard run got canceled also... sorry..  

Post Reply
Jamesvette
I love my Chevy Chevette!
Posts: 8
Joined: 04/13
Posted: 05/01/13 05:47 AM

Well, as it turns out it doesn't seem to be the servo.  I ended up removing the instrument cluster to verify the voltages at the instrument panel connector.  I found that the lt blue wire to the clutch switch was damaged at the terminal, and would read good sometimes, and when tension was applied the wire would disconnect.  Now when I turn the ignition switch to run the solenoids in the servo click.  All voltages and resistances read correct at the connector, but the cruse still doesn't work Frown  

The speedometer reads correct, what's left, the instrument cluster?  I don't believe there is a way to test it.

Anyway, still no working cruse, but now I know how to troubleshoot a cruse problem Tongue  

Post Reply
waynep712222
V-6 Camaros rule!
Posts: 35
Joined: 04/13
Posted: 05/01/13 09:03 AM

looking at the diagram ..

do you notice the cluster is grounded via 2 different locations...


D1  and D3..    

D1 goes to ground location  G101...   the instrument cluster ground..

D3 goes to the same ground that is shared with the AC system..  could be G104 or G110 depending on the info..



since you seem to have the cluster out.. or know how to take it out..

you might want to carefully examine the cluster circuit boards for cracked solder joints..

its totally possible that the electronics are DAMAGED because of the intermittent wire.. or the repair job...

Hondamainrelaycircuitboard



this is a  slightly later C4... this ground wire is behind or beside the battery tray.. and is really important that its taken apart and cleaned...

87 C4 Underbatterygroundconnection  

Post Reply
waynep712222
V-6 Camaros rule!
Posts: 35
Joined: 04/13
Posted: 05/01/13 09:05 AM

somewhere on the web are several great articles on repairing the various circuit board connections and interconnects in the cluster...  

Post Reply
12 Last
TO TOP