87 GT auto trans cruise control (Page 1/1)
WonderBoy APR 16, 12:48 PM
If anyone gets a chance, can someone snap a couple good pics of the switches/connectors on the brake pedal for an 87 2.8 automatic? Ordered a harness off eBay years ago, tucked in the wires for later when I was putting the interior back together, now trying to restart the project again. However I have this suspicion that either the harness I got was for another year, or for one with a standard transmission.

Thanks.

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Curtis

1987 Pontiac Fiero GT:
<Drives like a Go-Kart, handles like a roller coaster>

[This message has been edited by WonderBoy (edited 04-16-2022).]

theogre APR 16, 07:48 PM
GM use several brake switches and isn't just stick vs auto.
Auto trans w/o OE Cruise switches are different then Cruise setup.
Maybe even different for 87 L4 vs V6 even w/ Cruise because Cruise Logic is built into the ECM on 87 and later iron dukes.

Pictures may help...
find 87 FSM or pay alldatadiy.com to get correct wiring diagrams for 87.

Cruise uses two brake switches.
one kill power to Dump solenoid in switch.
other "cancels" without turning off the Cruise box in another switch.

auto cars has a plug for TCC lock as well on top of Brake lights. I think that wire/plug move depending has Cruise or not.

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(Jurassic Park)

The Ogre's Fiero Cave

fierosound APR 17, 07:03 AM

quote
Originally posted by WonderBoy:

If anyone gets a chance, can someone snap a couple good pics of the switches/connectors on the brake pedal for an 87 2.8 automatic? Ordered a harness off eBay years ago, tucked in the wires for later when I was putting the interior back together, now trying to restart the project again. However I have this suspicion that either the harness I got was for another year, or for one with a standard transmission.




PDF of 87 Service Manual
http://fieroinfo.com/manual...M_Service_Manual.pdf

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3.4L Supercharged 87 GT and Super Duty 4 Indy #163

WonderBoy APR 17, 07:46 PM
First off, this is about adding cruise control. And no, am not going the digital/electronic route. Want this as stock as possible the way Mr. Hulki and crew 'intended'. I read a lot about it years ago, saw many threads here on PFF, now going through it again. I do have my 87 GM Fiero Service Manual. It's confusing.
Looking here:
Troubleshooting the Cruise Control by Oliver Scholz

quote
First, the Fiero used two fundamentally different approaches to the cruise control. The 1984-1986 4 cylinder and all V6 Fieros use a separate cruise control module. It is located behind the carpet on the driver side center console. To access it you need to remove the radio console and flip the carpet aside. Fortunately these units don't go bad very often. I have never seen one break. But you may need to access the module connector for troubleshooting. The second system involves the 1987/88 4 cylinder Fieros with DIS. On these cars, the ECM takes care of the cruise control functions. The advantage is that you can troubleshoot the system with a scantool. The scantool tells you whether or not brake and other switches are on or off. The downside is that you need access to a scantool and if the problem is in the ECM, replacement is expensive. But again, the ECM hardly ever goes bad, the far more frequent reasons for cruise control problems lie in the mechanical parts of the system. Before we get into those, let's have a very general look at how the cruise control system works.


Doesn't say anything about the 87-88 V6. The 87 FSM is kinda screwy, as it doesn't explain nor show very much where the main connector goes from the cruise control module (which I have in place in it's cozy spot as specified in manual).
Putting a cruise control in an non cruise car?
But this was meant for an 86, and that Fiero had the connector built into the harness behind the radio to connect to the cruise control module.
87 V6 ECM have cruise in it?

quote
Cruise... I don't know just what is differant in the harnesses. The module might splice in but I doubt it. I'm not sure if there's enough space for it there either. I believe it usually lives under the carpet on the driver's side of the tunnel like the sub woofer amp does on the passenger's side.

There is a small black plug on the harness near the ECM... That plug is the cruise control interface to the ECM. In theory you would need to connect the V6 cruise to that plug and the system should work to a point... you'll still need to figure out how the module gets it's VSS feed.


Of course mine, being built without cruise control doesn't have that connector (possibly, if that's where it's supposed to be, can anyone confirm?). Pictures speak a thousand words, and I'm not seeing it in the FSM.
This bad boy?:



Possibly here, behind the I/P area?


Browsing/searching the 87FSM doesn't show really where this connects to (another GM documentation fubar?). Nor does the 88FSM.




This 8 wire connector harness is long with mounting plugs, and the inside of the shifter/console area has the holes for them. So Ogre you may be right.
My Current installed switch (on bottom insert hole) and the one that came with/on the module cable:

I guess I'm gonna have to start tracing the wires/colors and splice accordingly near the ECM, AGAIN if that's REALLY where the connector should be. But not in the manual. Or will go to the mall and see if anyone has that firewall-2-ECM-ALDL cable since it looks like its one piece.

Hoping this will turn into a good write up for others. The FSM, to me, can't be fully trusted.

[This message has been edited by WonderBoy (edited 04-17-2022).]

WonderBoy APR 17, 09:36 PM
OK, maybe that connector to the main harness really is or might be up above steering column. I'll check tomorrow.
fierosound APR 23, 10:11 AM

quote
Originally posted by WonderBoy:

Browsing/searching the 87FSM doesn't show really where this connects to (another GM documentation fubar?). Nor does the 88FSM.



The 86 FSM has better cruise control diagnostic diagrams that may help. See section 9B
http://fieroinfo.com/manual...o_Service_Manual.pdf
WonderBoy APR 24, 04:13 PM
Since I've got limited space to work with and parts from the instrument panel cluster, center console glove-box, shifter/ash-tray assembly, aux gauge pods, dash speakers, etc I'm holding off on removing the dash (again). I've got a new skeleton arriving from Matt (mmeyer86gt/gtp) next week. Once I've got that, then I'll remove the dash to see if that bugger is there to the left of steering column. Monday will be leaving for Ohio, so won't be able to continue with this side project till I get back.

The 86FSM almost says the same thing, which I find odd.
Found this module for sale on eBay from an 86, (I've got the 87 version) and grabbed the pic:


For 86's, the cruise control module harness goes into a connector behind the radio area:
(Thanks to an archive post pic)

86/87/88FSM's don't show where the other end of the module harness goes.
I've got Roy Orbison She's a Mystery to Me on replay. (yes, really)
But, if anyone wants to chime in feel free.

[This message has been edited by WonderBoy (edited 04-24-2022).]

WonderBoy JUN 11, 02:38 PM
Finally got a chance to disassemble my interior pieces (for the 50th time) to look for the hidden connector that connects the other end of C245 from the 87 cruise control electronics module to the 'spinal cord' harness. Since I was going to be installing -->Matt's 3D printed skeleton<-- since mine was beyond repair after many band-aid fixes, for the first time I was able to get a look at the area under the big black rectangular support part of the old skeleton in front of the ECM to see what lurks beneath. And voilà: I Found it!
The person who sold me the CCE Module with harness was great to keep those retainers clips in perfect condition.
Cruise Control Electronic Module Connector Location:

Since I had the entire dash out also, I routed the switches/stalk/cruise-light-mod (see below) the proper route.


Thanks to Fierofreak00 for this write up
Adding CRUISE Light:





Instead of cutting the original instrument cluster indicator light filter, I carefully hand ground away the coating with a Dremel wheel. Then lightly polished it. If I had to do it again, I might've used a tad of brake fluid. The extra layer of plastic does slightly weaken the light passing through, but to me looks more stock. I also applied very-very small amounts of black RTV with a tooth pick around the small CRUISE cut-out when I went to put it on the original light filter and let it sit with tape/tooth pick across it and clamp for good adhesion. Plus the Buick Regal donor that I got the CRUISE filter from had a slight curve to it due to age and sitting in the junk yard heat. Had to redo it 3 times (always happens to me! Third times charm) to get it right and aligned. Also FINALLY took care of the pegging temp gauge fix I've been waiting to do at the same time while I was in the instrument cluster.

Got a rear wiring harness with the cruise connections off eBay. The description said no cuts or splices..., my luck ain't that great. Was missing the driver-side rear side marker socket, and looked like someone already spliced and repaired with excessive extra wire. Not to mention someone stopped short of cutting the connector for the Servo/Solenoid/Trunk light. I redid the entire harness. All new electrical tape. New split loom. New routing clips and retainers. Solder and heat shrink. Cherry.
Rear Wiring Harness:






Installing the engine bay Servo/Solenoid/Bracket/Throttle-cable parts:

All components are used pulls, except the Tank is from TFS. With a nice coating of POR-15 and some blue. It's also advised to test the vacuum dump solenoid before installing. Apply 12 volts to it at the connection point using any 12 volt power source. You should hear a >click<. Remove the 12 volts. Using a clean piece of tubing, attach to inlet and blow into it. Air should flow freely through it out the back port with the filter clip attached. Mine was clogged. By sticking a piece of small gauge solid copper wire along with some PB blaster in the inlet/outlet ports and wiggling around for a while. LUCKILY, I got something loose and blew out a couple small pieces of rust. Makes sense since when I got the setup, the inlet port was rusted a bit inside. Apply 12 volts again and blow through it. Air flow should stop. Using a multi-meter, check for ohms on the 2 pins. Should get around 25 OHMS. There may be a replacement for this solenoid if yours is shot: ACDelco 214-357. Haven't bought it, so I'm not sure if it's a normally open valve. And may have to plug one hole and remove the built-in mount screw.

Installing the Vacuum Reservoir Tank (The Coffee Can):
Another set back. Ugh. Because I have non-stock exhaust headers and cross-over pipe, the actual mount points for the tank puts the bottom of the tank 1/8" away from sitting on the exhaust system. I've got the WCF 2.8 "Shorty" headers. So I had to mount the tank elsewhere. Luckily there's plenty of space below the vapor canister and air-filter. Using an existing mounting hole, adding one to the bottom leg of the air filter mount and then fabricate my own extender bracket, the project can proceed.
Original Tank Mounts.

Too close!

New location with bracket.

4" of clearance from cross-over pipe.

Question, I know I need to make some heat shields. Diaphragm feels like it's gonna melt, and Tank still gets toasty enough where I think it might melt the plastic valve piece. Should I make 2 shields covering them? Or should I just take the original 2.8 cross-over heat shield and modify just that and be safe? Suggestions appreciated.

Installing Pedal Switches:
Old brake pedal switch for 87 automatic with third brake light (GM 25529881) needs to be replaced with GM 25529880. I also needed a new retainer for it GM 25527405 since I butchered my old one. The other brake pedal switch needed for the cruise control is GM 10024217. Also needed the retainer for it, GM 9796744 / 10075405.



First test drive:
Ignition key to 'ON', I hear the >click< (engaged) from the vacuum dump solenoid. Press break peddle, >click< (dis-engage), release brake >click< (engaged). That's good. Got my gal up to 45 MPH, switched the Stalk to 'ON', then 'Set'. CRUISE light came on my dash, but was not holding speed at all. Tapped brake, CRUISE light went off. Those circuits are good. OK, while on this test drive I though I'd test to see if the CCE module was communicating with the ECM and speed sensor. Going 20 MPH, tried to set cruise. No go, no CRUISE light. That's good, since it's only supposed to operate at 25 MPH+. Head home for more trouble shooting. Using this write up from the forum, Cruise Control Testing, along with the 87FSM, I was able to narrow it down to the Servo. Removed the Servo.

Let's take a look inside and see if it can be salvaged. Don't want to spend $50-$120 on a re-manufactured one. I wasn't thinking when I was talking it apart and putting back together to take pictures, I cleaned and painted internal metal parts as I was repairing.
The Servo:

After continuity test described in the picture, using your 12 volt power source, hook up A and C. You should hear a >click<. Now hook up C and E. You should hear a >click<. In my case, A and C the solenoid didn't engage (no >click<). Off comes the Servo cover.




Here's what I got on my plate. Ha!









Now, I find it odd that the vent valve core doesn't have a cover. That's more rust and failure waiting to happen. But looking underneath the housing/cover, I see some indentation as if it's supposed to be hitting the cover when that solenoid is dis-engaged. That one must rust up all the time since it's exposed.
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Found this YouTube video after my repair, and disassembled Servo again to do some more preventive maintenance on the Vacuum Valve and didn't realize the entire plastic structure can be removed from the diaphragm where there is another rubber seal I wanted to check.
GM Cruise Control Vacuum Servo Actuator Repair - 1987 Buick Century
Added a homemade seal for the Vent Valve core/actuator.

Anyone know what I should coat this with so it wont rust again, but needs to be smooth and won't wear off?
****

Installed the servo back into the bracket in the trunk and hooked everything back up. Turned ignition to 'ON'. Got the >click< from the dump solenoid. Switched the stalk Cruise Control function to 'ON', another >click<. Vent solenoid now operational. Turned stalk 'OFF'. Test drive time. Get my gal to 45 MPH, stalk set to 'ON'. pressed the 'SET' button. CRUISE light on, foot off accelerator and holding. However has some hesitation, but working. Went to the interstate. Got up to 70 MPH. Worked like it should. Success! Gonna look at vacuum issues to see what the hesitation issues are at non highway speeds. And also cylinder compression tests (man I hope the results are good if and when I do it).
john carter OCT 05, 10:24 AM
Is the cruise control module behind the black plastic panel? I pulled the carpet back up to the radio and see no module. I don't want to go further than necessary. Thanks
olejoedad OCT 05, 02:08 PM
It's behind the front of the driver side plastic panel.