A while back I made notes from a BB posting about a modification to the wiper relay which would allow variable sweep intervals. I'm afraid that my notes are not so clear that I can still make out whose good idea this was. If any of you readers are the author of the original post, which I have been unable to find in the archives, please accept my apology for failing to give credit where due. Here are my notes, incomplete as they are regarding attribution:

• Modification for variable-interval wipers: Modify the existing relay, behind the footrest on the driver's side. Remove the 56 K ohm resistor (green-blue-orange) and solder two wires going to a 300 K ohm potentiometer which you place among the switches in the center console. Then you can adjust the interval between 1.5 and 35 seconds.

I think I'll try this. Any other suggestions?

Thanks very much in advance!

So, I completed the modification to my wiper relay as described in my earlier post. And thanks again to the author of the original post containing this neat idea. I'm happy to report it works as advertised!

Here's a summary of how I went about the mod in case you'd like to try it yourself:

I modified the black wiper relay found on the drivers floor under the sheet metal footrest, relay # 1-235-067 (896459). The 56K Ohm resistor to be removed on my relay was tan in color and had colored bands starting from the "top" of blue, blue, orange, and gold. You can check with an ohmeter to be sure you're removing the right component.

I connected some small-gauge wires in place of the resistor and weatherproofed them through the base of the relay. I placed the hole so that the wires wouldn't interfere with the relay connector when the relay was re-installed.

At the other end of the new wires I attached a linear 250K Ohm variable resistor, wired so that clockwise rotation of the knob reduces resistance and the wipers sweep more frequently. The new resistor and knob have found a new home in the dash, easily reached from the steering-column wiper switch.

(On the variable resistor I used, there are three unmarked terminals, think of them as A, B, and C. Use any two. With clockwise rotation, A:B provides increasing resistance, B:C provides decreasing resistance.)

The 250K Ohm variable resistor I settled on allows sweep intervals from about one second to about 25 seconds, which is a range I'm happy with. For comparison, an unaltered wiper relay provides a sweep interval of about ten seconds when the wiper switch is in the interval position.

I also tried this mod with a 100K Ohm variable resistor. That set-up gives an interval range of about one second to about ten seconds over the nearly 300-degree full rotation of the knob. More knob-turning for more fine-tuning, if that's what works for you.

Good luck with it!

I was hoping you'd have some replies, as I'm interested in doing this myself--I was just thinking the other day that variable delay windshield wipers are pretty much the only "new car" thing that I wish the Volvo had.

Good luck doing the mod, and let us know how it goes!

Laine: Maybe you've figured this one out already yourself. If you haven't, see above post for an update for how this fix worked out for me.