V70 key, fob and central locking unit

[V850B5254T]

About remote control, malfunction and solution.

Most remotes have a bad habit, no matter what they are used for: your car lock, your TV or other. They let moisture, sweat and dirt migrate into the contacts.

The indication of the problem is that you have to press harder and harder on the button to make it work.

The push buttons are made of non conductive silicone rubber with a conductive rubber pad placed inner siden of the silicone. When the button is activated, the conductive rubber pad is pressed against two cupper traces on the electronic circuit board below, shorting them.

When moisture and dirt have had the time to seep in between the electronic circuit board and the conductive rubber (depending on use, this takes from months to years) the contact function will deteriorate to a point where even a very firm pressure on the pushbutton will not activate the function.

Almost all of my remotes (car, TV, CD player etc.) has been through the following process.

Remove battery (-ies)

Disassemble the plastic enclosure (the difficult part).
In some remotes the two plastic parts are hold together by screws or clips molded into the plastic parts - or both.
It can take some time to figure out where to push, pry or pull to get the parts apart without inflicting too much damage,
but with some persistence they will eventually come apart.

Other remotes have the two plastic parts welded together. It is a production process where a high frequency vibration
melts the surface where two plastic parts meet. They can usually only be seperated by force; e.g. a Drehmel or similar tool
with cutting disk or a knife. It might not look pretty afterwards, but it will work. If the damned thing doesn't work anymore
you might as well try it.

When the plastic parts have come apart, you will usually find an electronic circuit board and a silicon sleeve with one or
more pushbuttons protruding. Make a mental note of the position of the parts for the later assembly.
Before you touch anything: When dealing with disassembled electronics you always have to take care about
electrostatics discharge, - it's an electronics killer. When handling this electronic board always start touching the battery
contact.

Cure
Wash the silicone rubber sleeve and the electronic board in a mild dish washing soap (the type you would use in the sink,
not in the machine) using a soft brush. Be thorough, but du not let the elecronic board soak in water for more that
necessary (15 - 30 seconds should be enough). While you are at it, clean the platic parts as well. While the electronic board
is wet electrostatic discharge is not an issue, but when it dries up you should be careful again.
Rinse with plenty of tap water. If your tapwater is clorined you should end with a bath in destilled or bottled water.
Blow away excessive water form the parts, compressed air is preferable, but a hair dryer will do.
Let all parts dry up for a couple of hours at normal room temperature.

Assembly
Remember to handle the electronic board by the battery contacts first. When replacing it in the plastic housing it can be
handled by holding it at the rim.
If you where able to disassemble the housing without breaking anything the assembly should be straight forward.
If you needed brute force for the disassembly, some kind of glue might be necessary. Silicone glue (RTV) applied with
caution can be used, but a lot of these products develops acetic acid when hardening and that's an electronics killer.
If it smells sour don't use it for electronics.

When you have replaced the batteries, go try it.

oakey

[Ritchard]

So I'm confused.

I need another key fob for my '98 V70 T5. I called the dealer, they said that none of those eBay ones will work, he says once they've been coded they cannot be changed. On the other hand we have the fobs on the FCP Groton site that the website claims I can program myself if I have the blinking alarm LED. BEJinFbk above says that any part # 9166200 from eBay will work.

What do I need to do to get a new fob? Is there a definitive answer someplace?

Thanks,

Ritchard

[BEJinFbk]

Your dealer is mistaken.

And if the Groton site is referring to '98's?
They are incorrect. Dealer programming is required.
Most 850's are programmable by owners, but not x70's.

Here's how it works for your '98:
The 9166200 fob transmits a unique, individualized code. (All it does is transmit).
(It's also an everchanging "Rolling" code, but that's not important right now).
The dealers scan tool, with the PIN for your car, sets the receiver in a "learning" mode.
The tech pushes the button on the fob and "teaches" the receiver/alarm module that fob's code.
IIRC, the car can remember 3 remotes and then the first code that was programmed gets pushed
out by the latest one in. I'd probably be a good idea to provide all of your remotes when you go in
to add a new one, just to be sure that they'll all still work when all is said and done.

In short? Your dealer is more than likely confusing your relatively simple '98 with later models.
I wouldn't hesitate to cheerfully challenge anyone that gives you the story that you got before.

[Ritchard]

Thanks BEJ for the clarification.

The FCP site does indeed say that their fob can be self programmed for my car. After further reading after posting above, I came to think they were mistaken.

So I can go to eBay and pick up any new or used #9166200 fob, and the dealer should be able to program my car to understand the fob. Good news. Thanks.

R

[stoutlogic]

I'm having the same issue. Both my fobs have sh*t the bed. They both still "function", but the top cap that holds the electronic guts inside is in way too many pieces for repair.

Crazy glue repair served me well for a couple years, but that's no longer a viable option.

Looks like I'm heading here:

http://www.ipdusa.com/product.asp?strPa ... rtRecord=1

Anyone try these? Way cheaper then dealing with Volvo direct.