Fuse 7 intermittently blows, all zones ok?

Tiny
ROYENGLE
  • MEMBER
  • 1994 ISUZU RODEO
  • 3.0L
  • V6
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
Start/Run Ignition Switch ok. Zones connected to fuse 7 (dashboard) works. While driving fuse 7 intermittently blows for no reason. Test Hazard Lights work ok. Test Heater blower relay ok. Swapped Start Relay ok. Dash gages all works ok. Check Engine lights ok. Replaced Alternator, gets 12.5 volts ok. Power goes to 5A at ECM, but where does it come out? Replace with new fuse 10/15 A, sometimes immediately blows, sometimes not. 8 Amps tested at fuse. I then connected a test light across blown fuse 7 and it resets circuit so new fuse doesn't blow it. I give up?
Wednesday, December 2nd, 2015 AT 10:09 AM

10 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
I assume you are talking about fuse 7 inside car. That goes to taillights, gauges power windows and vehicle speed sensor. Anyone of those could cause your problem. I would suggest check wiring under car for chafing against the frame or partially broken going back to taillights and speed sensor. That may be your problem. If it's fuse 7 underhood that is strictly for heater controls so check for the same thing going to blower/resistor as well as control head for heat air cond that shold be a 20 amp fuse 10 amp for inside car.
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Wednesday, December 2nd, 2015 AT 12:04 PM
Tiny
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As I already stated, fuse 7 is under the dashboard. When fuse 7 is blown Hazard lights switch still works turn signal lights, so they are not the problem. As I already stated, there are 3 zones connected to fuse 7, see wiring schematics. All checked out ok, while fuse was blown. Replacing the fuse sometimes blows instantly or goes on working for another day. Connected Relays checked out ok too.
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Sunday, December 6th, 2015 AT 10:57 PM
Tiny
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Is there any Isuzu Rodeo OR Honda Passport owners out there that's had this fuse 7 problem?
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Sunday, December 6th, 2015 AT 11:06 PM
Tiny
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  • 48,601 POSTS
Hazard lights are operated by fuse 3 fuse 7 goes directly to t/s switch then lights, so check switch wires for a short in steering column then check grn/wht wires for same along frame with grn/blk wires. Those go to lh and rh trun signals. The harness may be moving a little while driving and grounding against the frame blowing fuse. It could also be power window circuit as it powers that as well so check power window relay and try to find when it blows, like what is operating when it blows. It also powers gauges and speed sensor which both have a yellow wire for power. Check those as well.
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Monday, December 7th, 2015 AT 6:59 AM
Tiny
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Wire schematic saysTurn Signal Flasher Unit's Brn/Wht wire gets power from Turn Signal Brn/Red wire to fuse 7 OR Hazard switch Grn wire to fuse 3. Therefore, when fuse 7 blows, no power to Turn signals, but if Hazard switch works Turn Signals, then there is NO fault in Turn Signal circuit, but the Brn/Red wire could be at fault.
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Thursday, December 10th, 2015 AT 10:35 AM
Tiny
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Also, the power window's master control console by the driver's side has two broken switches. This console is hard to find, and very expensive to replace. I cannot find the Power Window's circuit on the schematics, are they connected to fuse 7, as you said to check it?
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Thursday, December 10th, 2015 AT 11:40 AM
Tiny
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Power window Relay schematic
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Thursday, December 10th, 2015 AT 11:52 AM
Tiny
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Power windows schematic
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Thursday, December 10th, 2015 AT 11:58 AM
Tiny
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I found the Power Window's Relay schematic, yes it is connected to Fuse 7.
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Thursday, December 10th, 2015 AT 12:10 PM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Fuse 7 goes directly to power window relay via a yellow wire see pic. If you have two broken switches I would imagine that is the problem. Pull the relay out and drive it see if fuse blows. If not you probably found your problem. Just like I said in previous reply to check or disconnect areas fuse 7 was connected to one at a time to locate where the problem is. You might try junkyard dog. Com for a used part, enter your stuff then they will contact you by email if they have it and how much.
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Thursday, December 10th, 2015 AT 12:16 PM

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