Speedo help?

[Laird Scooby]

Originally Posted by siadow

Hi

I’ve done some simple soldering before but never used a solder sucker!
Simple wire to wire stuff for guitar leads, I’m a music teacher!

What I don’t have I’ll buy + watch YouTube tutorials!

What do I need to try?

: )

I'll put together a mini-tutorial and explanation tomorrow, if you can do guitar leads you should be ok doing this but it needs a bit of dexterity (shouldn't be a problem for a guitarist) and a bit of timing. You probably won't need YouTube but you might want to practice the technique on an old broken 1980s radio or similar if you just happen to have one floating around!

[jor]

It's the car outside that has a n/f temp gauge...
From your reply I'm not quite sure whether or not you have got to the FAQ yet, as it has photos of the connectors about which you ask.
Can be reached by: volvoforums.org----> volvo owners club (near the top)----
--->car info------>700/900/90FAQ------->main faq files------->electrical instruments-----> speedometer failure (also odometer failure)
It begins as below:
Diagnosis: Speedometer Head, Wiring, or Sender Unit? How to tell if the fault lies with the sending sensor on the rear axle, the wiring to the speedo, or the speedo itself: Sensor Test. [Peter KL Milne]

jor

[Laird Scooby]

Originally Posted by jor

It's the car outside that has a n/f temp gauge...
From your reply I'm not quite sure whether or not you have got to the FAQ yet, as it has photos of the connectors about which you ask.
Can be reached by: volvoforums.org----> volvo owners club (near the top)----
--->car info------>700/900/90FAQ------->main faq files------->electrical instruments-----> speedometer failure (also odometer failure)
It begins as below:
Diagnosis: Speedometer Head, Wiring, or Sender Unit? How to tell if the fault lies with the sending sensor on the rear axle, the wiring to the speedo, or the speedo itself: Sensor Test. [Peter KL Milne]

jor

The sensor is ok.

[siadow]

Just caught up with replies.....
Been at school today. Distance learning stuff during these Covid times.

Anyway, looking forward to more help soon.
Thanks guys

[jor]

Originally Posted by Laird Scooby

The sensor is ok.

I'm pleased its ok as there's a lot less to do, but how do we know (as both are n/f)?

Originally Posted by siadow

Ok
Dr google found me lakes!
I’ve emailed to see if they have instrument cluster for sale!

Hopefully will not be needed, but from previous experience there may be a long wait for a mail reply, it's probably better to ring (!)
Should you eventually need anything sent I am happy to pick up and get it sent on.

jor

[Laird Scooby]

Originally Posted by jor

I'm pleased its ok as there's a lot less to do, but how do we know (as both are n/f)?



Hopefully will not be needed, but from previous experience there may be a long wait for a mail reply, it's probably better to ring (!)
Should you eventually need anything sent I am happy to pick up and get it sent on.

jor

The sensor is ok on the OPs car because the ABS light behaves as it should. If it wasn't ok the ABS light would come on above ~20kmh or 12-15mph.

[Laird Scooby]

Originally Posted by Laird Scooby

I'll put together a mini-tutorial and explanation tomorrow, if you can do guitar leads you should be ok doing this but it needs a bit of dexterity (shouldn't be a problem for a guitarist) and a bit of timing. You probably won't need YouTube but you might want to practice the technique on an old broken 1980s radio or similar if you just happen to have one floating around!

The bits you'll need are some 60/40 tin/lead solder and a fine tipped soldering iron (25-30W) and :

https://www.ebay.co.uk/itm/185mm-Sol...l/231879756759

To prime the solder sucker, push the button down the length of the hadle towards the button on the side until it clicks.

Using a bit of fresh solder, apply the soldering iron tip to the suspect joint until it begins to melt - now dab the fresh solder on until it just begins to flow.

Remove the solder and swap your hand to the solder sucker keeping the iron in contact. Place the tip of the solder sucker as close to the joint as possible then press the release button and watch the old solder disappear - remove the iron quickly!

Let the joint cool for a couple of minutes (mainly for the thin plastic PCB to recover) and you'll notice the old solder has a matt, mottled appearance. Once cooled aply the soldering iron tip until it just starts to alter then apply some fresh solder to the joint - not the iron tip.
Once flowed to cover the joint nicely, remove the iron and allow to cool.

Let the area cool completely before moving on to the next joint nearby.

The two joints i suspect may be causing your problem are those on what i believe to be a pull-down resistor on one leg of the sensor inputs to the speedo.









The two contacts in question are ringed in the last image. The first image shows them after reworking, after that the PCB was cleaned with IPA and an old toothbrush then rinsed with extra IPA to get rid of any remaining flux.

When doing the desoldering, imagine a 4/4 beat - first two beats are heating the joint and applying the fresh solder on the third beat, 4th beat is remove the solder with the sucker and remove the iron.
Resoldering is similar but the 4th beat is remove the soldering iron once the new joint has flowed evenly.

[siadow]

NEw solder kit has arrived. I’m planning on practicing on old pcb board from old PC in attic. Practice today and tackle the real beastie tomorrow.
I’ll keep you all informed.

[siadow]

BEfore


After!





Refitted and test drive.....

Still all dead!
In fact my test drive was blighted by intermittent loss of power!

I’ve had issues with fuel pump relay 2 years ago and again since December.

I bought 2 replacements and have tried both. I thought problem had gone for good until today.

Could it be condensation in petrol tank?

Car is kept in cold garage and used only around town maybe twice a week?


I’m sorry to post my failures, but any more suggestions re Speedo and now powerloss would be gratefully appreciated.

Thanks

Steve aka siadow

[Laird Scooby]

You've posted the same photo twice Steve so they both look the same.

The slight loss of power is a bit of a vague description though. Can you expand a bit?