Compass info

[wws944]

Padgett, I bet you, and maybe a few other Reatta owners, remember the Edsels that had the buttons in the steering wheel that were used as the gear selector for the transmission.

Lotta Mopars had that in the late '50s and early '60s.

One of these years, I'd like to dump/disassemble the PROM(s) in the BCM and see if there are any remnants of the compass code in the '90 BCM. Wouldn't it be interesting to get a compass module and have it display in the odometer area (like a lot of newer cars do)? Bet it wouldn't take much code.

[Ronnie]

I knew Mopars had a push button for the trans on the dash but I wasn't aware they had buttons in the center of the steering wheels.

Like this Edsel wheel:

[padgett]

Ayup. Optional with the 400 engine ? Am not a F*rd person. Aways thought the Sunliners had a fat derriere.

[Guest Richard D]

I [and others] have installed Buick Roadmaster compass mirrors. They have the compass in the upper right hand corner of the mirror, but still have the map lights found on the bottom side of the mirror [similar to the Reatta]. They are not self dimming.

My Red has the Roadmaster rear view mirror with compass, the Riv. compass installed thru the CRT and a Garmin GPS. I have always been directionally challenged so think this is not unusual.

The Black will have a Roadmaster rear view mirror w/compass [coming soon] and the GPS. In this car I did not need the novelty of the CRT compass.

Rawja's instructions were easy to follow. The only change I did was installing the unit in the wiring under the dash as I did not want to go thru the bother of running the wires. Because of that decision I don't think it is as accurate as it would be installed in the correct location, but then again I only use it to show off what these cars are capable of [electronically].

At first it did seem a little dark without the mirror lights. So I replaced the courtesy foot well lights with very bright LEDs and the dome light with LEDs that can be slightly aimed foward and the car is nice and bright again plus I get the auto-dimming.

[wws944]

I knew Mopars had a push button for the trans on the dash but I wasn't aware they had buttons in the center of the steering wheels.

Like this Edsel wheel:

Ronnie, I wanted to get back to you on this. I asked a friend of mine who is an expert in vintage Mopars about this. The Mopars only had the buttons on the dash (from '56 Powerflite through '64 Torqueflite). As you note above, Edsel had buttons in the steering wheel hub, and according to him, only on the upper series Corsair and Citation in '58. He also noted that the '56 Packard had push buttons - mounted on a pod on the side of the steering column - but not in the wheel itself.

[padgett]

And just FYI, the reason they stopped after '64 was that the fed mandated a standard shift pattern (PRNDL). The same year they mandated that Harley put the gearchange on the other side which meant that for a couple of years Harleys had a very strange linkage on the shift mechanism.

And to make your day, earlier GM automatic shift patterns were N (no P until later) DLR to make it easy to rock from low to reverse when stuck. Nowadays it is possible to go from R to D passing N along the way without hitting a detent. With a typewriter it was easy.

[Reattatude]

And just FYI, the reason they stopped after '64 was that the fed mandated a standard shift pattern (PRNDL).

Why does this not surprise me? Edsels scared me when I was a little kid! Ugliest car ever!

[padgett]

You mean the horsecollar ? You do not want to know what the front of a 69 Cougar was called.

[Howard]

Regarding pushbutton transmission controls, the 1957 Mercury had a pod to the left of the steering wheel.

[padgett]

So did the Facel-Vega.

[SeanR]

AFAIR the numbers are on the compass module connector port, plug the connector in and the number/color issue should be readily resolved.

My install allowed for a full data loop to the compass as shown in the FSM. Apparently the factory just dead-ended a single data line at the compass, hence the lack of the fourth wire which should not affect operation.

BUMP. I'm hoping this thread can answer my question about my module only having 3 wires. It's from a 90 Trofeo, 12V, Part #1647056, and the three wires are #1 port empty, #2 tan, #3 purple/white, and #4 black/red.

Do I need that #1 pin ? :eek:

[SeanR]

compass module pic.

[Guest 88atta]

My posting not appropriate; sorry.

Edited April 23, 2012 by 88atta
Will send PM to querry Rawja on anodizing from the dash. (see edit history)

[Guest Corvanti]

My posting not appropriate; sorry.

actually i had the same problem with accessing the link. it looks awesome!!! and would like to do the same at some point... hope the info becomes available!

[KDirk]

Sean,

There are actually only three connections required. 1 wire (tan) is the serial data line, the other two are 12V+ and ground. I cannot remember off hand which is 12V+ and which is ground, but think the purple/white is 12V+. If you take the black plastic enclosure off the module (is held together as a clamshell with little snap tabs) the circuit board inside is marked with the pin assignment of the female (module) side of the connector, one is clearly marked "GND". This will clarify it for you. I have the Trofeo module in my 88, and distinctly remember having to figure it out this way as I didn't have service data for a Toronado to tell me which wire was which.

As an additional bit of useless info, where most modules have two serial data line connections (one in, one out) for redundancy, the compass module uses only one which is why the 1 cavity is empty. When you take the cover off the module, you'll see the two solder pads for the serial data line are tied together on the circuit board, so that if the second serial data line wire were added, it would just be paralleled to the existing one.

Do not know if the same is true of the 88/89 Rivi version in the metal enclosure as it is different internally.

KDirk

[SeanR]

Wow, not sure what I missed that was inappropriate? Thanks for confirming the pinout Kevin. Also, this one clearly says 7volts since it came from a 90 Trofeo. I read from a different post that it was 91 where they did away with the CPS.

[Ronnie]

Is this the info you guys are looking for?

Compass Module Installation - '88 & '89 Models*-*ReattaOwner.com

[SeanR]

Is this the info you guys are looking for?

Compass Module Installation - '88 & '89 Models*-*ReattaOwner.com

Yes and no. It needs some editing to include some finer details not mentioned.

[Ronnie]

Please provide me with the finer details that are missing and I will be happy to add them to Rawja's otherwise comprehensive tutorial on installing the compass module.

Thanks Rawja for providing the information used in the tutorial!

Edited April 23, 2012 by Ronnie (see edit history)

[DAVES89]

If you have a 90 or 91 model without the CRT do what I did. Find an electronic mirror from a Buick or Cadillac and wire it to the accessory fuse on the drivers side. You get a compass and an electrochromic dimming mirror, either function can be turned off from the front of the mirror. The only drawback is unless you find one with the reading lamps it can be a little dark up front. I found an ultra bright LED lamp for the dome light and it lights up the car fine with help from the foot well lamps and door lights, plus it runs cool so it will not discolor the plastic cover.

I have looked in a great many GM cars for a mirror with the trifecta you mention, Compass, Auto Dimming, and Reading Lamps. I don't belive it exists. You can get two of the three Compass/Reading Lamps, Auto Dimming Map Lights, but not all three.

For me and my professional life it is the compass and reading lights.

I am so directionally impaired that the Red has 3 compasses [the Black has two], the one in the mirror and one from a Riv that works thru the CRT and a GPS.

[KDirk]

Sean,

You are correct, the 1991 and later E-platform cars had no CPS, 1990 and back DID have one. So, you will need to tap off the 7 volt filtered power from the CPS to drive the module you have, hooking it to 12V will probably let the magic smoke out. Lucky you aren't using an older compass module in a 1991 model car, or you'd have to cook up a 7 volt regulated power supply to run it.

Dave,

I am 99.9% certain that a compass auto dimming rear view with reading lamps was made by Gentex (the supplier for these mirrors to GM and many others). However, I don't know that GM ever used one in that exact combination of features. Years ago I had a JC Whitney catalog that had the full line of Gentex mirrors, and I think the top end model that had all 3 features (the trifecta) was north of $250.00. Wish I knew of a model of car that used it, so I could tell you what to look for in the yard.

One nice thing about the Gentex mirrors is that they all had a vacuum fluorescent display for the compass so it matched the look of the digital dash readouts, unlike the Roadmaster one which you and I have - it has a backlit LCD. It looks ok, and works great, but looks just a bit out of place I have thought.

The drawbacks to the Gentex mirrors is that they snap mount to the slug on the windshield, rather than using a set screw and are very difficult to remove as a result. They also have a bigger base containing the electronics that would make mounting in the Reatta very challenging as it sits so close to the headliner.

KDirk

[Guest Mc_Reatta]

You'll probably end up with a thermometer readout as well.

Wonder if the thermistor in the front of Reatta would be compatible?

[wws944]

I actually have one of the Gentex mirrors that has map lights, auto dim, and compass. It is model GNTX-221. IIRC, it came out of a late-90s Intrigue. It has the newer 'snap in' mount that Kevin described. You have to use a special tool to release it without breaking the windshield. (The car I got it out of already had a broken windshield...) But I think they made them with the set screw too.

In fact, there are a couple exactly like mine listed on ebay right now. One claims it came out of a Toyota Matrix, the other out of a Lincoln Continental. Another similar one from a Caprice, and so on.

Kevin (or anyone): Did the E-body Cadillacs of that time period have built-in compasses and compatible compass modules? Or was it just a Riv/Toronado thing?

[KDirk]

Walt,

Far as I know, the compass "module" was unique only to the 88/89 Rivi and the 89-92 Toronado and Trofeo, and on those only the VIC (touchscreen) equipped cars had the compass module. No Cadillac had the compass module, as there was no place to display it's output without the CRT display setup.

I don't know how the module presents it's output on the UART dataline (if there are packets sent that contain actual directional data in ASCII form like "NORTH" and "WEST" or if the output is byte-coded and then translated to human readable form by the receiving module (in this case the CRTC). I'd have to hook an eavesdropping bus monitor onto the ALDL in my 88 to see if I could pick it out from amongst all the other data, and the E-platform cars have a very "noisy" bus as there is a lot of data being sent at all times to keep the IPC displays correct in real time.

The mid-late 80's Eldorado and Seville had a one line 20 character VFD alphanumeric display for a driver information center that would show date, time, avg speed, avg and inst fuel economy, RPM's, volts, and temperature, but no compass feature was present on these to my knowledge.

The first year I saw a compass auto-dimming rearview was the 94 Deville, and it was optional. Thinking about it now, the 92 Eldo and Seville (that was the year for their major redesign, the Deville got it two years later in 94) may have had it as an option, but I am not sure.

I think it became standard equipment about 1997 or 98 in the Deville, and was probably already standard on the Eldo and Seville prior to that as they were always a bit more up-level models and got the newest features standard ahead of the SDV.

I've never seen the fully fitted Gentex model you have in person, only in a catalog. That would be the way to go except for the snap mount (which I cannot stand - have this in my Deville and it is a dog to get off).

Be careful of which model car you get one out of, some OEM Gentex mirrors have red displays instead of green.

KDirk

[Rawja]

Apparently the compass module will work with a single data line, and was equipped with the single line from the factory.

I came up with my wiring by utilizing the service manual which shows two data lines (loop). Another case where the manual differs from reality I guess.

[SeanR]

Power lines were routed up and over the steering column and to the hanging power supply. I unhooked the power supply connector (everything in the car goes dead when you do this). Looking at the power supply connector, there is a blue and a beige termination stay within the connector, you want the beige set, which is numbered. power to the unit goes into #16 and the isolated ground goes into #7. push the beige wire retainer back into the connector and reattach to the power supply.

Looking for clarification. I consider "beige" power supply connector to be gray. Never heard of calling gray, beige. I think of beige as brown or light brown and this one is blue and gray pinout. Am I counting 7 and 16 on the connector side or the CPS side? When looking at the grey/beige pinouts from the wiring side, these slots are empty. So am I connecting to empty pinouts? :confused:

IS there an easier place to tap into 7 volts rather than using this connector? Or should I be using that junction box to the far right of the 2nd picture?

Edited April 30, 2012 by SeanR (see edit history)

[padgett]

I could use another compass/reading lights mirror for the foundling. Have one in the white and just jumped the existing reading light wire to run the compass. Only problem is I have not replaced the little lamp. Was really a simple job, all the wires you need are in the header.

[SeanR]

IS there an easier place to tap into 7 volts rather than using this connector? Or should I be using that junction box to the far right of the 2nd picture?

I answered my own question rant. The D7 and D16 on the grey side of the CPS power connector. Now if I could just get the compass calibrated correctly. I used a phone app and either the compass is wrong or the phone app is wrong but both were out of sync with each other. I pointed the phone app due North, but when driving the car compass kept say I was driving East or North East.

[Rawja]

The compass on my iPhone never works right in the car. When I did this mod it was pre-smart phone and I used a regular old compass.

Just knowing where north really is when you calibrate should be adequate.

[SeanR]

The compass on my iPhone never works right in the car. When I did this mod it was pre-smart phone and I used a regular old compass.

Just knowing where north really is when you calibrate should be adequate.

I installed this compass underneath the tape player. I used velcro and its just sitting on top of the relay center. I wonder if its getting electrical interference because the compass is sometimes all over the place and seems to change if I tap the brakes. It will cycle from all different directions. At one point I was traveling South, and it said I was headed Northeast, then back to South.

[DAVES89]

I put mine in the area to the left of the steering wheel. I keep calibrating it and it keeps "wandering" as yours does. That is why I went to the rear view compass mirror. I keep the CRT compass mirror just for showing off. [And that it is installed and too lazy to take it out].

[Rawja]

I can say that it works perfectly mounted under the rear window shelf. That's where it was installed on the Riviera, probably for the very reasons you're describing.