connector and dashboard

richard.z · Post by **richard.z** » Wed Jan 28, 2004 6:35 am

Hi,

I've been away for a while, due to the fact that I nearly gave up on my 480. I want to give it one last try though to get it running satisfactorily.

My speedometer and odometer are not working properly because (I think) the connector on the back of the dashboard is too loose. I mean the rectangular one, with 3x5 connections. Apparently some of the connections don't fit properly anymore. Very often my speedometer and odometer suddenly stop working, mostly after a bump, and sometimes a bang on the dashboard gets them working again for a short while. Does anyone have advice how to tighten the connectors, or is there some kind of stuff I can use to improve conductivity between loose contacts?

Any help would be very much appreciated!

The problem is especially nagging since my infocentre isn't working either, and I use my odometer to decide when it is time to fill up the petrol again.

Richard
480 turbo automatic 1991

David Thornber · Post by **David Thornber** » Wed Jan 28, 2004 12:27 pm

Sounds like dry joints (resulting in intermittent contacts) on the circuit board at the back of the speedo housing, could be near any of the connector pins. Best solution would be to carefully re-flow the solder joints around any dodgy looking pins.

richard.z · Post by **richard.z** » Wed Jan 28, 2004 4:46 pm

Sorry, I am afraid it isn't.

The problem is, like I said, that some of the connectors have lost their grip on the pins. I think this might have happened when I took it out to resolder some dry joints, like someone suggested. Out of the frying pan....

How do I know? Some of the wires can be moved up-and-down very easily.

RichardZ
480 turbo automatic 1991

Murf · Post by **Murf** » Wed Jan 28, 2004 6:06 pm

you could try finding a car in the scrappies, cutting the plugs off and then resoldering them onto your cars wiring loom. not an enviable task but it depends how much you want your dash to work!

lee · Post by **lee** » Wed Jan 28, 2004 6:25 pm

I have also had this problem but since i have pushed the connectors back in they have been ok.

My idea was to push the plug in and then hot glue them in place.

Murf · Post by **Murf** » Wed Jan 28, 2004 6:38 pm

good idea, will be a bugger to change the illumination bulbs though!!

kap · Post by **kap** » Wed Jan 28, 2004 7:42 pm

Salut ,

an other idea as Lee could be to seal the moving wires inside the connector to avoid they can escape when pushed on their pins

richard.z wrote:...How do I know? Some of the wires can be moved up-and-down very easily.

silicon seal or polyurethane or acrylic shouldnot matter !

A +

bbf · Post by **bbf** » Wed Jan 28, 2004 9:23 pm

what about soldering directly on board ? like desoldering all pins of conector and cutting wires from original conn and solder directly? or soldering longer wires in between or even adding custom connector on them?

that's what i would do.

richard.z · Post by **richard.z** » Thu Jan 29, 2004 5:56 am

Hi guys,

I read many interisting ideas, but it seems there is no reaction yet of anyone who actually encountered the same problem and solved it.

IMHO soldering is always the worst solution, and should be avoided if possible, since solderings tend to crack as a result of the vibrations of the car. Those who had to resolder the joints on the print plate should know.

RichardZ
480 turbo automatic

kap · Post by **kap** » Thu Jan 29, 2004 6:24 am

Heey ,
you 're really pessimistic !

richard.z wrote:.....since solderings tend to crack as a result of the vibrations of the car. Those who had to resolder the joints on the print plate should know....

well resoldered with appropriate electronic product should provide you some miles before cracking again if any

Problem was that in the past Volvo supplier , the job wasnot really well done

A lot of guys suffers of the some control panel erratic behaviour as number of VEM comes with probs and need to be resoldered

Let us know which solution you finally choose for such a prob

A bientÃ´t

richard.z · Post by **richard.z** » Thu Jan 29, 2004 6:40 am

Sorry, I am not pessimistic. Any car electrics mechanic will tell you this. Soldering is only an option if there is absolutely no stress or vibration on the joint. If there is, it will crack. Owners of alfa's, maserati's (or any other italian car) will be able to tell you horror stories as well. That is why clasp connections are preferred in cars. They're more reliable..... or they should be

I don't want to sound patronizing, but believe me: I've been there.

What I want is to restore a solid clasp connection.

RichardZ
480 turbo automatic 1991

kap · Post by **kap** » Thu Jan 29, 2004 7:16 am

Sorry Richard ,
I misunderstand your intention to restore by anyway a clasp connection

richard.z wrote:What I want is to restore a solid clasp connection.

I fully agree to solve in that way , the original one , but secured that time

Good luck

bbf · Post by **bbf** » Thu Jan 29, 2004 8:35 am

Well i dessagree with you, richard.z. The only reason why there is so many connectors instead of solderjoints is from practicality reason. Assembling and servicing is much simpler and quicker with deatachable connectors. and even connectors are not so reliable (specialy in a 480). They tend to oxidate and gain resistance or even producing it's own voltage (it was in my case - heavily corroded connector on lambda probe). And you have problem with a connector too, if i consider your case. So don't forget the mechanical stress they're liable to.
Cold solder joint happen on forinstance on large capacitors, switches or releys soldered on printed circuit board or connector pins (are yours "riveted" or soldered to PCB?) and even they happen mainly because of lack of tin around those mechanicaly stressed components - this is the cause of a serial manufacture.

Believe, I am an electronic engineer, i've seen bad and good soldering.

Hope you'll solve your problem quick and easy!

Ernie · Post by **Ernie** » Thu Jan 29, 2004 8:56 am

Richard,
I really hope that it is "just" the connector that causes the disfunctioning of the speedometer and odometer. Check the functioning and correct position of the sensors too! Had similar problems once and had to replace the speedo-sensor on the (auto)transmission box.

richard.z · Post by **richard.z** » Thu Jan 29, 2004 9:29 am

Ernie,
Thanks for your tip.

Like I said, often the speedometer starts working again for a short period of time if I bang on the dashboard. This makes me confident that it's just a loose connection.

My info centre isn't working either. That problem can be anywhere. It occurred after my radio was stolen. Yes, the red/grey wires in the radio loom are connected

Richard
480 turbo automatic 1991

Renter · Post by **Renter** » Thu Jan 29, 2004 12:06 pm

I got the same problem.
Did you guys also notice that when the engine goes back to idle, when you come to a stop, the rpm goes down to 600 and slowly restores itself.
When the speedo is working on my dash, it does not dip that low.
Also letting go of the gas does not immediately slow rpm, it looks like its lagging behind. I notice this also during upshift, the rpm lags when i let go of the gas.
When dash and meters are functioning normally rpm drops immediate after letting go of gaspedal. Must be another sensor involved that has to do with idle valve and or throttle position.
Is the speedo thing connected to these functions also ?

Funny thing is that my fueltank meter is working fine and the number of km's i can do with remaining fuel in the tank is updated and correct.
I would have expected that the km's to go update would be screwed up too, but it is not.

I can often solve the problem by doing a short brutal dragrace, usually it picks up. (only to find out that with the next brake action it cuts out again.)
Its happening more often now than before so coming summer i'll take it apart and solve the problem.
Don't need the car for next 3 months, and besides its cold outside.

Rgds, Renter

dralphs · Post by **dralphs** » Thu Jan 29, 2004 9:43 pm

Hi

From memory when i had the same problem with my speedo (1993 2.0 es), yes the engine rpm dipped low and/or stayed high when the speedo wasn't working.

i don't have a diagram to hand, but i'm sure if you look at the fuel injection diagram you will find that there is a signal from the speedo into the fuel computer. Hence if the speedo isn't working the rpm is upset.

I can only assume the ECU uses the speed signal as well as the rpm to work out when to reapply fuel under deacceleration to improve engine economy?

In my case it was a dirty contact on the sensor plug. Reseating and a little cleaner sorted it out

volvofox · Post by **volvofox** » Thu Jan 29, 2004 10:33 pm

I was the first here on this site to dismantle the clock housing, and to find haircracks in the pin solderings, it was one ofg my first posts on the old site.

before I also thought the connetors were worn "like a prostitute"./.

I went to the scraper with a side cutter and cut out other connectors (they had other colours, but that doesn't matter if you cut and connect wires one by one) I used old fashioned screw connectors and had a long job..... that brought me no result.

the second examination i found haircracks on the connector pins as stated.

On a friend car I worked on the speedo, that only worked on some punishment.

I fond a bad corroded stain on the small print directly under the speedometer in the housing.(toothbrush and contactspray)

one thing I also know is that the wires from the speedo (look it up in the e-schedule) run through a wrapped wire to prevent magnetic influence (much like an antenna cable) it is very britle, and breakable. Even seen a car on that some made a bypass to the sensor with ordinary cable.

Am not afraid to remove and open the dash again ! look at the things i did.

ps: the "new" connnectors I have plentyfull greased with ordinary lithium based grease. Hmm, greasses, and fills!

Renter · Post by **Renter** » Fri Jan 30, 2004 9:28 am

Thanx, now i now for sure my 480 is behaving "normally"
I'll rip it apart this summer, sounds like a nice job.

Rgds, Renter

Ettore Bugatti · Post by **Ettore Bugatti** » Fri Jan 30, 2004 11:44 am

I had last week removed the dash to change some bulbs, but when I wanted to install it back in to the car I found no room for my hands between the dash and the back of the 'gauges' to put the connectors firm on it. The wires are too short. How do the people here put the connectors back on? btw the connector for the infocentre switch was no problem

Volvo 480 Club Europe