1999 V70na Replace Electrical Portion of Ignition Switch!!!

paredown · Post by **paredown** » 05 Jun 2015, 08:55

I finally got back to this, after Ozark Lee recommended replacing the ignition switch after getting some random rough idle/stalling weirdness after hitting rough sections of road.

Well--as always--his instincts were right. No sign of any ongoing problems (touch wood).

What I was not prepared for was a significant increase in drive-ability--smoother idle etc. It is hard to put a finger on--but the car just runs better.

So what all gets routed through those mystery pins on the switch that would affect overall performance?

Anyone who has nagging code/drive-ability issues on a a high mileage car should get their ABS module redone by Matty Moo, and then replace the ignition switch before moving on to other possibilities.

For mine it was ~$55 at FCP Groton https://www.fcpeuro.com/products/volvo- ... 90-9447804--watch for the model change by VIN for the slightly newer cars.

Post by **precopster** » 05 Jun 2015, 11:12

Basically all power to engine loom and sensors goes through the switch; it's a pretty important junction point.

Post by **BEJinFbk** » 05 Jun 2015, 23:34

Not really. To be more specific for the electrically inclined readers here,
some of the systems run directly through the actual ignition
switch contacts, but a large percentage of the cars switched electrical
systems are drawing current through several "accessory overload" relays
that are energized by the ignition switch. There real juice for those
systems runs through the 105 & 106 overload relay contacts.

Post by **precopster** » 06 Jun 2015, 06:30

Yep and all those other circuits have an almost tiny percentage of failure rate so if the ignition hasn't been replaced on a 93-00 car (depending on VIN) chances are it will solve 99.665% of gremlins.

paredown · Post by **paredown** » 10 Jun 2015, 11:15

Well my gremlins seem to have vanished. I cleared all the codes (most were related to the weird stumble/rough idle after hitting rough road) on the weekend, did a quick 100 miles to and from Newark on Monday--no codes reappeared.

Today I got it through inspection. Even the code related to the purge cycle has not come back, although i don't expect that to stay away indefinitely...