What all does the underhood 25A blade fuse power ?

I've changed it at least twice over the years as a precaution, but actually had it blow today when restarting.

Car is running now with a new 25A fuse, just working on my checklist.

Thnx, Rgds, Dave.

It supplies the fuel injection and ignition computers... as well as the main fuel pump.

If your fuse holder is original, I'd replace it with one of the fancy "waterproof" ones from IPD. Also clean all of the fuel injection/ignition system grounds.

I cleaned all of the contacts/grounds, dabbed them with contact grease, and replaced the fuse holder in my '90 245, and the car starts sooner and runs noticeably better... even though things didn't look bad at all.

-Ryan
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Athens, Ohio
1990 245 DL 130k M47, E-codes
1991 745 GL 280k (Girlfriend-mobile)
Buckeye Volvo Club

Pick up same "waterproof" fuse holder from any of the _Mart type stores for about three bucks...no shipping.

Would this fuse & holder contribute to hard starting in wet weather? I have a terrible time getting my '89 wagon to start after it's been sitting in the rain. Was thinking about changing the distributor cap in case there was tracking going on, but maybe this fuse holder is the culprit. What do y'all think?

Rain troubles classicaly equals problems with dizzy cap or ignition wires.

But on an old 240 you have to think about that fuse and also the main fuse holder by driver's left ankle.

I still suspect the wires or maybe the cap. Because wet wires would short to ground, and leave you with a weak or missing spark. Fuse problems usually are current not flowing which would be the same wet or dry. I think if a fuse is so wet that it's shorting to ground, the problem would be a dead battery, not some engine electr. or fuel system component that is temporarily not working.

For wires, idle the car in a dark place at night and look for sparks in engine bay. Not fun when it's raining but if you don't see sparks on a dry night it might be worth a wet head to look on a wet night. For dizzy cap, the only thing is to pop it off and look in there.

I try to look at the underhood fuses on all our three cars a couple times a year. Clean up the fuse's contact blades and apply dielectric grease if you have it (small pack for a dollar or two will cover several projects). I usually remove fuse holder (pull battery ground connection first to protect yourself!!) and clean it up inside when we get a "new" brick. Fuse holder opens up via two small release tabs on the narrow edges. With tabs free, tip back the top like a hard-pack cigarette box, then the guts will come free.

Main fuse panel inside car is a candidate for water dripping. Drain is in pinched + welded edge running under rocker panels. At the jack point(s), I think? Poke a wire up there to help clean it. Pull up carpet edge by door opening; there are plastic plugs. I'm told that with plugs out you can vacuum the passage there. If clogged with old junk it backs up and you get drips where your feet + legs are and on the fuse panel. That's for the water from the air-vent intake grill. I still have to check mine. I bet they're a mess.

For fuse panel, I clean up corrosion with a pen knife blade tip. Goes in the small holes in fuse holder contact tabs, as edge of hole is the fuse's contact surface. Be careful; don't pop yourself.
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Sven: '89 245 NA, 951 ECU, open-front airbox, E-fan, 205/65-15's, IPD sways, E-Codes, amber front corner reflectors. Wifemobile '89 245 NA stock. 90 244 NA spare, runs.

This is a pretty excellent response by Sven.

The only thing I can add is that on an older car (all 240's are nearing 15 years now), there's never just a single problem. Only one may manifest itself (the proverbial straw that broke the camel's back), but there are always other potential problems in the background that may be exacerbating things. This is especially true for later 240's (LH 2.4/3.1) that are smart enough to compensate for a bunch of problems, and only start screaming for help when one of them gets truly out of spec. For example, when my AMM went caput in my 1990 245, I also found some holes hiding in the main intake hose that likely had been there quite a while.

In short, a cap/rotor/wires/plugs may be your immediate problem, but dirty fuses/contacts/grounds may also be problems.

It's worth pulling things out, and inspecting/cleaning them. That's the beauty of the Volvo community: getting info on pootential problems/solutions from others and then checking up on them on your own car.

-Ryan
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Athens, Ohio
1990 245 DL 130k M47, E-codes
1991 745 GL 280k (Girlfriend-mobile)
Buckeye Volvo Club

Are these fuses available in Auto Zone etc. I broke the fuse cap while taking it off for cleaning .Then I joined the broken cap to main holder with epoxy.
You mentioned LH 3.1 I have a 1990 240 Wagon which seems has 3.1
I want to know if the main processor and the one which is below the fuel pump relay are the same as on other 240s. I was looking for spares in junk yard for bad times.
Regards
Gopesh

Thanks for the responses guys !

I usually keep that blade socket greased, but it is probably time I took it apart and had a really good look at it.

Rgds, Dave.

Don't overlook the red wire from fuse holder to (from) Battery + terminal. We have had 2 or 3 no-starts reported due to rotten corroded wire strands there, sometimes causing a buzzing Fuel relay (starved for current).
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Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Interesting comment on buzzing sound - had that recently on my old brick (88 250 glt saloon 140k) and was told it's low fuel level and pump noise - filled the tank to the toop and buzzing stopped...
meeeeanwhile........ i get a loud cluck (a bit like when you stick your tongue in the roof of your mouth and pull down sharply) from midway in the dashboard at random, anyone knopw that this could be? a relay of some sort maybe?

for you lucky guys in usa, a tank full here in u,k. set me back about 110 dollars... so fuel economy is a BIG issue... new forum topic perhaps??????????

Main pump can be noisy due to sucking bubbles (not a solid fuel stream) from the tank. Low level exposes a short hose connecting tank pump to outlet pipe.
This hose perishes with age, letting air get pulled in. Full tank excludes the air, but tank pump output is still degraded. Not good for main pump, IMO.

The noise you describe could be a relay, but how to tell?
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Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Another good point! I scrubbed that up too. :)

Thanks!
-Ryan
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Athens, Ohio
1990 245 DL 130k M47, E-codes
1991 745 GL 280k (Girlfriend-mobile)
Buckeye Volvo Club

Bruce, can you recap the wiring map? I keep forgetting the routing.

Battery + goes to white fuse holder - correct?
Fuse holder powers ign. ECU and also fuel pumps?

Junction box next to fuse holder -
Gets battery power from?
Supplies ? circuits?

I know it must be in Bentley.
But I think you know this stuff cold...

Thanks, from the other Bruce
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Sven: '89 245 NA, 951 ECU, open-front airbox, E-fan, 205/65-15's, IPD sways, E-Codes, amber front corner reflectors. Wifemobile '89 245 NA stock. 90 244 NA spare, runs.

"I know it must be in Bentley.
But I think you know this stuff cold..."

It is in the Bentley, but not always easy to find. What I know (not cold) I learned from digging into the diagrams. But I still double-check them before posting.

Looking at the '89 diagram, the 25 Amp fuse is NOT shown anywhere near the Battery (Item 1 at Grid B1). Instead you'll find it in the LH 2.4 sub-diagram at grids K4,5 and L4,5. If you don't know what to look for there, go to the Alphabetic listing (390-42) where "Fuse (25A)" is listed at grid L5 as item 212. Back on L5 you'll find 212, with an off-page arrow pointing to item 1, which the Numeric listing on 390-43 identifies as "Battery" — you just have to believe the fuse is attached to the Positive terminal (Faith-based documentation).

Looking at 212 on L5 again, go thru it like the voltage does to a "dot" junction that runs between 214 (LH ECU) 4 and 217 (Fuel relay) 30. When the Fuel relay is energized (2 relays actually), the voltage leaves the relay via terminals 87/1 and 87/2 (shown also as terminals #1 and #2). I think you can follow the lines to see where the relay voltage goes.. Another line from the dot junction goes up to item 211-5. Check the Numeric listing to find out what item 211 is.

The Junction box on the inner fender is identified in the Alpha listing. When you locate it on the diagram you'll see a line coming in from the battery + terminal. That's the other small red wire. Follow the 3 lines leaving the junction box and you'll answer the rest of your question.
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Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Whew. Thank you. Now I will have some clue of what I'm looking at when I delve into that diagram in Bentley.
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Sven: '89 245 NA, 951 ECU, open-front airbox, E-fan, 205/65-15's, IPD sways, E-Codes, amber front corner reflectors. Wifemobile '89 245 NA stock. 90 244 NA spare, runs.

Go for it! But be advised there are some errors and omissions in both the Alpha and numeric listings for different years.

Sometimes a new item (in the diagram) doesn't show in the listings. Looking at the next model year may help.

And sometimes the grid references after the first 2 pages (after ref G) are way off. You have to hunt around for a given item number.

These are not Bentley errors. The diagrams are copies of the Volvo Green Book back page fold-outs.
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Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.