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Thread: What's this funky fuse?
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mwpayne1
Redlining
Posts: 239
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posted December 13, 2006 04:37 PM |
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What's this funky fuse?
Inside the cab behind the seat, passenger side, there's an electrical box. Has a 50 amp fuse (piece of metal), and two 2A fuses that look like thin pieces of zigzaggy copper surrounded by thin plastic. These are blown. Can't find anything like these at advance auto.
Anyone know where to find these buggers?
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ovquick
Redlining
Posts: 253
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posted December 13, 2006 06:27 PM |
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Funky Fuse
I think the "funky fuses" make the ammeter function.The REPU ammeter is not in series with the load, that's why there are two "funky fuses"
____________
Manteca Mazda Asylum
where a boy and his cat live, without adult supervision
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mwpayne1
Redlining
Posts: 239
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posted December 14, 2006 03:59 AM |
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Good info. I have no accessories...lights, radio. Are these fuses tied to this?
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bliffle
Revvin Up
Posts: 95
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posted December 14, 2006 08:21 AM |
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I'm interested since the ammeter on my 74 REPU doesn't operate. My guess is that the 'funky fuses' include a 'shunt' that is inline with the battery cable. The purpose of the shunt is to develop a small voltage as current flows thru it (to/from the battery) so that the small voltage can be read by a high-resistance voltmeter which functions as the ammeter. That way they don't have to feed all the current thru a real amperage meter, which would involve a lot of high-current cabling. I guess I gotta remove the bench seat to get at that box. Then the trick is to devise an appropriate shunt.
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Brad
Rotorhead
Posts: 1672
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posted December 14, 2006 01:22 PM |
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50a is the main fuse. when it pops the truck no go. run out of fuses - stranded. the other two are for the ammeter.
replace that fuse box with a circuit breaker from a car stereo shop and buy a voltmeter instead of ammeter.
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-brad-
74 REPU Lawn Green
81 Rx-7 racecar. 12a J-
Bridge
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mwpayne1
Redlining
Posts: 239
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posted December 14, 2006 01:27 PM |
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The 50a is fine, truck will crank. I just have nothing else. I guess the only way to know for sure is to replace the thing with an updated fuse box (or ckt breaker).
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roaddancer
Hauling
Posts: 127
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posted December 14, 2006 07:08 PM |
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According to my old book and memory, the 50 amp piece is the shunt,allowing just enough resistance to force a small amount of curent through the fuses to the ammeter. My first repu's meter didn't work either. I suspect if the strip is replaced with a plain fuse, it stops the ammeter function.
Hope that helps!
____________
formerly
rx2/3/4/cosmo,repu,94 rx7,
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ovquick
Redlining
Posts: 253
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posted December 14, 2006 07:47 PM |
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Ammeter
Bliffle, if your "funky fuses" are good the problem can be on the backside of the dash. A little contact cleaning and the ammeter will functiononce again.
____________
Manteca Mazda Asylum
where a boy and his cat live, without adult supervision
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bliffle
Revvin Up
Posts: 95
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posted December 15, 2006 09:35 AM |
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I've gotta look this subject up in the Haynes manual (when I find it). Now I'm getting worried about the REPU electrics because last winter , in a downpour, my headlight/taillight circuit shorted out and blew a series of fuses. It dried out in the spring. Good thing I didn't need it in at night during the winter.
I'll try cleaning the ammeter contacts, since I'm trying to keep this as stock as possible. The ammeter tells you how good the alternator is charging, and the voltmeter tells the condition of the battery, roughly. It would be nice to have both.
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roaddancer
Hauling
Posts: 127
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posted December 18, 2006 10:33 AM |
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Check the runoff from the back edge of the hood opening to see if the rain was dropping directly into the fuses. There is something wrong with the shape of that lip that contributes to the "rain on the toes" leak so common in these trucks. Mine is filled up with sealer and it makes it worse.
An upgraded fuse box can protect the wiring.
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formerly
rx2/3/4/cosmo,repu,94 rx7,
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