Saab Central - Technical Help
Classic Saab 900: Door repair and maintenance
This article kindly written and supplied by Fred Lane
Variable delay intermittent wipers on a 900?
Windscreen wipers can be quite clumsy things, but I've always thought the Classic 900 wipers an elegant design. If you've driven a 900 for a while, you probably no longer notice the way the passenger side blade sweeps a shorter arc and doesn't come into your view, or just how well the water runs off the screen. The shallow screen allows the blades and arms to be short, so the wipers do their job without racing stick/slip and judder across the screen.
A rainy day in one of the flat screen euroboxes will remind you how good the old Saab is in the wiper department. (My worst wiper experience was an Opel Ascona where, in heavy rain, the two wipers just conspired to move a shallow pool of water around the screen in front of my face.) The wipers on the families other car, a VW Golf, make a good attempt at building a river up the right hand screen pillar, presumably just in case you hadn't found the existing ill-placed screen pillar enough of a hindrance to your view of the world. However the Golf redeems itself with an elegant variable delay intermittent windscreen wiper control. There are no knobs to twiddle. You switch off the wiper with the normal control, and switch back on when the screen needs wiping again. From that point on the wipers run at the delay interval you've just set. This works for any interval from 1 to about 40 seconds. If you switch the ignition off the delay is reset to a standard 6 seconds. I traced this bit of intelligence to a microchip in the wiper relay unit.
Obviously the reason I'm writing this is that the VW wiper relay just happens to be a plug in replacement for the standard 900 and 9000 unit and probably quite a few others. This means you can have variable delay intermittent wipers on your Saab, with no extra wiring or messy add on knobs. There are some other differences; you get an extra wipe you didn't really need as you switch off intermittent, but intermittent always starts with a wipe not a delay. Also the wipers run on for three wipes after using the washers rather than the original five. I've done some homework on suppliers. VW charge £35 (part number 357 955 531). They have used at least four manufacturers, Doduco, Beru, Kostal and Bosch. Doduco, German made, was fitted on the 94 Golf's and uses an SGS Thomson chip. I haven't found a UK agent. Beru (part number 0 900 301 082), also German, is on later Golf's and uses the same chip in a half height relay case. Beru tell me they no longer make this part. The Kostal (377 955 531) is Brazilian with a Motorola chip. The German car co (www.germancarcompany.co.uk) has supplied me with both the Kostal and the Beru for about £15 each. I prefer the surface mount construction of the Beru. I haven't see a Bosch (part number 0 986 335 058), but they tell me it's available and retails for £20.
I've tried all except the Bosch in my 900 and have been using the Beru for most of the winter. I now enjoy the Welsh drizzle. It's falling at about a wipe every 12 seconds today!!
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