I recently aquired a 1987 Thunderbird Sport 5.0. Just about to get it inspected and the Digital Instrument Cluster (Full) spedometer and information area ped out. Got a doner from the boneyard and it does the same thing???? Wiring harness, Fuses or WHAT?
Any and all help would be appreciated!!!!
Tony P:birdsmily:
If you've got the cluster out of the car, check the bulbs. If ONLY the speedo part of the cluster ped out this is likely the problem. There are two bulbs for each cluster section. The bulbs are halogen but you can replace them with normal 194 bulbs.
If the whole cluster went out I'd put my guess on the cluster illumination relay. It's in the center stack (the part of the dash that houses the radio, HVAC controls, etc) on the left side. You might also want to check the fuses (Not sure which fuse number is for dash lights but I'm sure somebody will chime in).
Thanks TC,
The two gauge areas have back lights but the second bulb in each cluster does not seem to be lit, could this be what illuminates the info????
Very well could be - it's been so long since I had a disco dash apart I forget. I'd recommend replacing ALL the bulbs while you have the cluster out. They're cheap, and it's a lot of work if you put it back in and another burns out.
Those halogen bulbs will pull right out of their plastic housings and you can install 194 bulbs directly in their places. It might be slightly dimmer (I noticed no difference in my '87 Sport) but it's easier than trying to track down expensive halogen bulbs...
I bought a Sport Coupe new in 87 with a digital cluster-never again. From then until 2003 I replaced the cluster illumination relay 5 times. Can you see the cluster at night and not during the day? At night the auto lamp dims the cluster. The contacts on the relay,(made in Mexico), weld together so it stays in dim during the day. The relay is located on a rack with 6 others just to the lower right of the steering column. I can't remember which one it is but Ford wanted the car for 3 days and the cost estimate was around $300. The relay costs about $12 at Ford and takes about 15 minutes to change.
I bought a Sport Coupe in 87 with the digital dash. From then until 2003 I replaced the cluster illumination relay 5 times. With the lights in autolamp at night the dash lights dim. With the made in Mexico relay the contacts weld together and during the day the cluster stays dim. The relay is located to the lower right of the steering column on a rack with (6) other relays. I can't remenber which one. According to the EVTM the wire colors are: brown,white/pink, lt. blue/red, black, white/lt. blue. The relay is used all over the car so you might be able to get it at a junkyard or at Ford for about $12+. If you go to Ford they might have trouble finding it or tell you it doesn't exist. In their electrical, vacuumn, troubleshooting manual it is shown on pg 83, wiring on pg 102.
Thanks Tommy,
I'll give it a try.
these will help,,
:D
dont forget to check out my DIY link above my pic/sig
there are several years of goodies in there for just about everything you run into on these cars.
and more,,,,,:hick:
and yet,, some more:cougarsmily:
If the two sections of dash on either side of the speedo are still lighting it ain't the relay. All of the disco dash's illumination bulbs are powered off the same relay, so if the relay was gone bad none of the lights would work.
Thanx all, let's go over what we've got:
87 T-Bird Sport
Full Digital Dash
Tach: backlit and functioning
Speedometer and Driver info center, back light seems to be working
However, imagine a Indiglo digital watch with backlight but no digital display.
So far this is what i've done:
All bulbs have been tested.
Swapped out the speedo and Info center with with same from donor.
only things left from the original to switch out would be the Mylar circuit sheet (ILLumination) or switchset 6 buttons Gauge, E/M, Trip & reset and Select & Reset.
Where is the speed sensor located?????
Regards & Thanks,
Tony P
The relay swop did'nt work!
Ok, so you've got backlight but no display in the speedo? Illumination isn't the problem, then. About the only thing I can think of is to check the wiring at the connector to ensure you've got all the powers and grounds (jcassity's images above should show you the terminals to probe) as well as the printed circuit, as you suggested. The speed sensor is on the transmission (where the speedo cable would normally be) but that isn't your problem. If it was, your speedo would show "0" all the time and the fuel computer would show incorrect information (but it would show information).
Does anyone have a step by step on trouble shooting the connector.
and/or the bulb mylar (green) circuit sheet????
Tony P
Normally I wouldn't be this anxious but i'd like to get this beast inspected and move on to some bodywork and MECHANICAL stuff!!!!!:bowdown:
Tanks
Tony P.
both screens get ther power from the same wire. it is on the clip behind the tripminder pod (brown clip). the power comes in and goes into the speedo and then is sent from there to the tripminder pod. so if both are out the problem wouldbe in the speedo.BUT, you said that you swaped out with another cluster and the same happened. so this would mean that the problem is not in the speedo or the circut tape. the problem is in the wires. and you know it's not the fuses or the whole thing woon't work. so what you have is either the power wire has burned out or got cut or the ground did what you needto do is take a multi meter red side to the power wire on the brown clip position #17(light green/yellow wire) and then ground the black side of the multimeter to the frame(ilike to use the steering columb for the stuff by the cluster) turn on the key and see if you get 12v if you do it's good if you don't the wire is bad and you'll either want to trac it down to see wher it went bad or run a new one. if it's good then your ground is probably bad but to check it is all you have to do is put the black sid of the multi meter on the ground wire wich is on the brown clip position #18(black/light green wire) and then touch the red side to a power i'd go with the power for the tach side since you know it works and it's right there. it's located on the other clip position #14(Light blue/pink) then turn on the key and you shold get 12v if you don't it's bad and you'll want to track it or run a new one. but it should be one of those two wires. as long as you don't have any display at all when on. if there is a ghost display when on but it looks like the light is off then it's the illumination wire #12 white/light blue. happy hunting. if these don't work give another shout out and we'll go from there.
to troubleshoot the display under normal situations where there is a display and numbers are present,, go to my DIY link above my sig.
In your situation,,,
The 87 shop manual 33-5-15 step 2 calls this fault as
"Display backlighted but blank", go to pinpoint test TB"
so,,,,,,,,,step by step
in a nutshell so i can make the novel before me become a summary,,
they say to unhook the battery
remove cluster
reconnect battery
turn on ign sw
check pin 14a is equal to batt voltage (min 10v)
next
check continuity from pin 15a all the way up to the bat ground cable
check for continuity from circuit 687 side of fuse to ground
check for blown run fuse on circuit 687
looks fairly simple but other than a power or ground issue, the manual calls out to replace the module. since you swapped out the cluster,, it rules in the fact you have a wiring issue as stated.
so,,, has anyone had a sterio system installed in this car recently,, do you notice any "hack job" going on with the wiring?
Also,, from what i have noticed, along the bottom of the actual speedo module itself, there is a narrow piece of flex print running into the module. I damaged mine when i pulled it out and had to solder in jumpers. Im laying money on that is where the problem is because i had the same issue, no number but i had background illumination.
scott
Raser & Scott,
Thanks, will use this very helpful information and get back to you.
Regards,
Tony P
no problem .if its not the wires then scott is probably right that the circut tape is the culprit but i would'nt think so sine it was bad on your replacement one too. but if it is just look on the tape to see if you can see any gaps in the circut line if not just fallow it from where the clip plugs in for the power and the ground to the bottom of the pod and check continuity through the circut tape. when you handle these tapes you have to keep in mind that they're 20+ years old and are usually pretty brittle. i don't like to futzs with them any more tan i have to.by the way rogers the name for use in the future.
below is the fragile flex print portion i spoke of. It is easily snagged bent up or snagged when the cluster is removed. I had to steal this pic from bondocougar but as you can see, even this unit is showing the signs of bent flexprint.
This area with the red arrow is where i had to solder in jumpers to make my numerical display work again.
To Roger, Scott and the rest,
Many thanx for your comments and suggestions!
Success!!!! The digital Instrument panel has been repaired.
The problem was in the Mylar circuit strip from "B" connector to the speedometer. There is a retaining pin that protrudes from the speedo through the rear I/C housing that is used to retain the mylar circuit strip, if the strip shifts it can become pinched on the pin and, as was previously stated these are 20 years old and somewhat brittle, cause the circuit tape was broken on both my original (ground & power) and the doner (power).
Was able to find this by simply using a multimeter to test for continuity from the plug contact area of the strip to it's terminal on the circuit board (see Scotts foto).
Installed two jumpers and was good to go!
Thanks again!
Tony P.
glad to here that you found it enjoy the car!!