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850 Dimmer Switch

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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warmblood58
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Year and Model: 1989 245
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850 Dimmer Switch

Post by warmblood58 »

Pulled 5 dimmer switches at a picnpull and not one would function so I pinned ports 1 and 4 from the backside and reinstalled switch which is on full. We have an excellent electronics supply house in our area. I am going to open switch and take to store owner to see if he can recommend a fix - - - I find it hard to believe that these switches cannot be repaired somehow - I will report back with results

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erikv11  
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Post by erikv11 »

Sorry, I am not following. Are you saying all 5 switches are bad?

That would be bizarre, I've never had one go bad, even have extra good ones. Not saying they don't fail, you can find posts about it, but it is uncommon.
'95 854 T-5R, Motronic 4.4, 185k
'98 V70, T5 tune-injectors-turbo, LPT engine, 304k, daily driver
'06 S60 R, 197k
'07 XC70, black, 205k
'07 XC70, willow green, 212k
'99 Camry V6 :shock: 153k
gone: '96 NA 850 210k, '98 NA V70 182k, '98 S70 NA 225k, '96 855 NA 169k

warmblood58
Posts: 163
Joined: 24 February 2016
Year and Model: 1989 245
Location: Medford
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Post by warmblood58 »

Yep, all 5 toast . . . no dimmer function which is why there are so many posts about bridging 1and 4 terminals on the switch. New dimmers are (850) over 150.00! Crazy!

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BEJinFbk
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Post by BEJinFbk »

What exactly is the problem you're having here?
If it's full on dash lights with no dimmer function
using 5 different dimmers, that would suggest
another issue in play.

If so - What do you get with no dimmer plugged in?
'98 V70 R - Well Equipped for Life Up North... ;)

warmblood58
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Post by warmblood58 »

I get no dash unless I pin 1 and 4 - My understanding is that the dimmers fry and then there is zero function as there is no connection through switch which is why people pin 1 and 4

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BEJinFbk
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Post by BEJinFbk »

Yeah, but FIVE bad dimmers? That just doesn't add up.
What do you see for voltage on pin 3 with the headlight
switch in the "parking lights on" position?
'98 V70 R - Well Equipped for Life Up North... ;)

warmblood58
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Post by warmblood58 »

You realize that I am talking about the dash light dimmer switch not the high beam flash arm stalk?

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BEJinFbk
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Post by BEJinFbk »

Yup. Here's what you should have at the dimmer connector:

Pin 1 - Brown/Orange - !2 volts from the ignition switch.
Supplies switched power dimmer when the key is on.

Pin 2 - Black - Ground.

Pin 3 - White - 12 volts when On from the headlight switch.
Provides 12 volts when the parking lights should be on.

Pin 4 - Pink - Dimmer output to all instrument lamps.

Pin 5 - White/Black - Ground when Off from the headlight switch.

Pin 6 - N/C


You also have a few posts describing some other electrical issues.
You may be dealing with some trouble from aftermarket work.
Check ALL the fuses in the car and find out what that black
fuseholder under your hood is for.
'98 V70 R - Well Equipped for Life Up North... ;)

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erikv11  
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Post by erikv11 »

BEJinFbk wrote:Yeah, but FIVE bad dimmers? That just doesn't add up. ...
This! 6 bad dimmers (including your original) out of 6? No way.

I'm no electrical troubleshooter, there are few better than BEJ for that I would give him a listen. But anyway if all 6 are truly bad now, then I would be wondering why your car is cooking them, not opening up the switches.
'95 854 T-5R, Motronic 4.4, 185k
'98 V70, T5 tune-injectors-turbo, LPT engine, 304k, daily driver
'06 S60 R, 197k
'07 XC70, black, 205k
'07 XC70, willow green, 212k
'99 Camry V6 :shock: 153k
gone: '96 NA 850 210k, '98 NA V70 182k, '98 S70 NA 225k, '96 855 NA 169k

warmblood58
Posts: 163
Joined: 24 February 2016
Year and Model: 1989 245
Location: Medford
Has thanked: 5 times
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Post by warmblood58 »

no, you misunderstood. My car had a bad dimmer switch, apparently they fail after some years of use. I harvested another five from pic n pull cars -these too were bad -

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