Fuel Pump Relay Repair

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.
1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
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Ozark Lee
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Fuel Pump Relay Repair

Postby Ozark Lee » Sun Jan 07, 2007 7:33 pm

Fuel pump relay failures are a common and frustrating occurrence with the Volvo 850. A failure effectively immobilizes the car and many owners, myself included, carry a spare relay in the car so as to not get stuck on the road miles away from any Volvo dealer. The relays are unique to Volvo and cannot be purchased from a standard auto parts store.

The signs of a bad relay vary but a failing relay will often emit a "buzzing" sound as it chatters.

Once the fuel pump relay has been diagnosed as the problem with the car it must first be removed from the upper electrical center. On North American cars it located under the fuse panel cover, under the hood, on the drivers side of the car. Access to the relay is achieved by removing the four T-25 torx head screws and lifting the cover panel off of the electrical center.


DSC02110.JPG


Upper electrical center.


DSC02112.JPG


Upper electrical center with the panel removed.


The fuel pump relay is relay 103. I have trouble getting my fingers around the pump relay to extract without first removing the 101/102 relay combo.

Once the relay is removed it is possible to actually repair the relay. Credit to Guy200 who first pointed out his successful relay repair.

The first step in the repair process is to remove the relay cap. This can be accomplished by carefully prying outward on the base of the cap with a pair of small screwdrivers on the sides that are adjacent to the labeled side of the relay. The cap has no real give to it so it is necessary to pry both sides at the same time.


DSC02113.JPG


Prying off the relay cap.


Once the cap is removed a small printed circuit board and the relay itself is revealed. Check for any obvious signs of bad things such as burned components, pitted or burned contacts on the relay, or loose solder joints. Assuming you find no obvious signs of damage the repair from here is to identify the two electrolytic capacitors. On my relay (898769000) the two capacitors were 100 µF and 22 µF respectively. The 898797000 relay may have different value capacitors.


Relay 1.gif


The suspect electrolytic capacitors.


Although not exact replacements I was able to locate suitable replacements at Radio Shack, exact replacements can be procured from either on line parts houses or a good electronics supply house. The Radio shack replacements carry the part numbers 272-1028 for the 100 µF and 272-1026 for the 22 µF. The Radio Shack replacements are both rated at 35 Volts which exceeds the voltage rating of the originals. The 22 µF replacement is exactly the same size as the original but the 100 µF Radio Shack replacement is slightly shorter and it has a slightly larger diameter than the original.


DSC02106.JPG


Size Comparison between the original and replacement capacitors.


Electrolytic capacitors, almost always, are polarized so be sure to note the polarity of the capacitors before removing them. My relay had the negative side of the capacitor oriented to the top of the PC Board and the positive side oriented to the base side of the relay.

Removing the capacitors requires unsoldering four solder joints on the bottom of the PC board as shown in red circles below.


Relay 2.GIF


Capacitor solder joints.


There are a couple of acceptable methods for unsoldering the joints. One method is to use a solder wick and the other is to use a solder sucker. I used a wick and still had difficulty getting the old capacitors out since the PC board is double sided and has the solder connection on both the top and the bottom. A solder sucker might actually be preferable. Get the joint good and hot but not so hot that the PC board gets damaged.


DSC02105.JPG


Unsoldering the capacitors.


Once you get the capacitors out check the lead holes to assure that they are open and not blocked with residual solder. If they are blocked they can be opened with the solder wick or the solder sucker.

From here it is a matter of installing the new capacitors. The originals capacitors were mounted so that the base of both components sat nearly flush with the PC board. Since the Radio Shack replacements are not the same size, and further so that I could assure that solder flowed to the upper PC board, I installed them so that there was about a 1/16 inch gap from the circuit board to the bottom of the capacitors. Double check your polarity as you are installing the new parts.


DSC02108.JPG


The replacement capacitors installed into the PC board.


Once the replacement capacitors are installed in the PC board it is simply a matter of resoldering the joints and trimming the excess lead length with wire cutters. Use a generous amount of solder and hold the heat on the joint for an extra couple of seconds to assure that the solder flows to the component side of the circuit board.

The last step is to reinstall the cap. The PC board rides between two grooves that are molded into the cap itself so be sure to align the PC board with those groves while sliding it back together.


The relay can now be reinstalled in the car and tested.


The relay I repaired here was one that croaked on me a month or so ago. I put it back in the car and it works perfectly. The total cost was $2.67 at Radio Shack.

...Lee
'94 850 N/A 5 speed
'96 Platinum Edition Turbo
'98 S70 T5
'99 V70XC - RIP - Wrecked Parts Car.
'99 V70XC - Nautic Blue
Previous:
'96 850 N/A
1989 740 GLT
1986 740 GLT
1972 142 Grand Luxe

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CarVolvo
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Postby CarVolvo » Sun Jan 07, 2007 7:38 pm

hey Ozark... who said volvo repair isnt as exciting as rocket science!

Thanks for your valuable contribution!
Proud Canadian Owner of: www.carvlvo.com

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MadeInJapan
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Postby MadeInJapan » Sun Jan 07, 2007 8:00 pm

Excellent job and write-up, Lee! Wowsa! :D

Obviously, this is going into the repair database. :idea:
'98 S70 T5 Emrld Grn Met/Beige Tons of Upgrades Mobil-1
'04 V70 2.5T Red/Taupe Some Upgrades Mobil-1
'07 S40 T5 AWD 6 speed manual! Silver/Black Stage1 Heico & Elevate
'07 S60 2.5T Blue/Taupe- my kid's Volvo

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Rob3
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Relays

Postby Rob3 » Tue Jan 09, 2007 1:11 am

Is there any chance that one of these other relays controls lighting?

Perhaps it can be similarly repaired?

Any ideas?

Thanks.

Rob3

Ozark Lee
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Postby Ozark Lee » Tue Jan 09, 2007 6:03 am

Rob,

Assuming you are talking about this one:

Image

Light control relay top.


Image

Side view of light control relay.

I would say yes.

That relay has four electrolytic capacitors on the PC board. I
'94 850 N/A 5 speed
'96 Platinum Edition Turbo
'98 S70 T5
'99 V70XC - RIP - Wrecked Parts Car.
'99 V70XC - Nautic Blue
Previous:
'96 850 N/A
1989 740 GLT
1986 740 GLT
1972 142 Grand Luxe

MadeInJapan
MVS Moderator
Posts: 12762
Joined: Thu Mar 31, 2005 2:14 pm
Year and Model: '98 S70 T5 '07S40T5
Location: Knoxville, TN American but born in Japan
Flag: United States of America

Postby MadeInJapan » Tue Jan 09, 2007 10:08 pm

Lee,
Any extra fuel pump relays for the cost of freight? :oops:
'98 S70 T5 Emrld Grn Met/Beige Tons of Upgrades Mobil-1
'04 V70 2.5T Red/Taupe Some Upgrades Mobil-1
'07 S40 T5 AWD 6 speed manual! Silver/Black Stage1 Heico & Elevate
'07 S60 2.5T Blue/Taupe- my kid's Volvo

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Rob3
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Location: California

Lighting Relay

Postby Rob3 » Sat Jan 13, 2007 2:43 am

Ozark Lee,

Thank you for the excellent Pictures and Information. I will save this.

My problems are due to the Relay marked "J" in the earlier Pictures. You can see 3 Relays marked with a "J". The center "J" Relay is not getting Power applied to the Coil from the Key Switch. This Relay runs the Headlights, Dash Lights (when Headlights are On), Backup Lights, Seat Belt Reminder, Rear Window Defogger, Rear Fog Lights, Turn Signals and ??

I'm fairly confident that the Key Switch is bad, but I haven't confirmed this. I did heat the Key Switch with a Blow Dryer and the Lighting started to work immediately.

I'll post when I get this fixed so that it might help others.

Anyway, thanks to you and to all who contributed.

Rob3

Jarkka
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Location: Helsinki, Finland
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Another variant of fuel pump relay

Postby Jarkka » Sun Mar 11, 2007 8:28 am

For those of you wondering why their relay does not look like the one pictured.

The relay on my 1993 850 GLT has a relay with a different component layout. In the side view picture, the capacitors would be the other way round, as well as rotated 90

MatDesign84
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Postby MatDesign84 » Tue May 22, 2007 3:14 am

This totally worked for me rock and roll and many many many thinks to the man who posted this. My friend btw over engineered mine for me meaning he beefed it up with higher rated parts so it shouldnt happen again.
Currently: 1997, 855 T5 | 1998 Subaru Legacy GT 2.5
Previous: 1997, 850 GLT | 1993, 850 GLT | 1988, BMW 325i, 1990 Volvo 240 DL
"That's good to know though in case they let loose again, but I swear if they do, I'll punch something." -jblackburn

Volgrrr
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Re: Fuel Pump Relay Repair

Postby Volgrrr » Mon Feb 04, 2008 9:03 am

[quote="Ozark Lee"]
The Radio Shack replacements are both rated at 35 Volts which exceeds the voltage rating of the originals.
There are only two types of car owners - those who own Volvos and those who wish they did.


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