help!!!1996 Blazer no dash lights or fuel pump

neon_boy82 · 11-02-2007, 03:37 PM

Hi everyone. My neighbor has a 1996 4.3L Blazer and it won't start. When he turns the key it cranks but the fuel pump doesn't turn on and the only thing on the dash that works is the shift indicator lights, no check engine. battery, etc. If he jumps the eninge fuse in the panel to the one beside it the lights and the pump come on but it still won't start. Is it a shorted wire or a relay or what? Any help would be appreciated. Thanks.

scottie · 11-02-2007, 04:00 PM

go through the fuses (dont "jump" any fuses, it could damage something) and check for any blown ones... there is also an inertia switch, that i beleive is in the cargo compartment that could have opened the circuit if he slammed the door or kicked it (it happens beleive me). id say check all fuses(under dash and in engine bay) make sure they all work.

crabtruck · 11-02-2007, 05:37 PM

Don't forget to check the fusible links to the junction block. What does work ? Blower, radio. turn sigs ? Welcome aboard.

neon_boy82 · 11-02-2007, 06:38 PM

everything else works except the fuel pump and the idiot lights on the display. He doesn't have a repair manual so we couldn't find the fuse box or the fusible links under the hood. Also he said a couple days ago that it was taking a couple tries to start his truck so I'm guessing the pump wasn't coming on the first time.

tjzz4 · 11-02-2007, 07:30 PM

I`d check ror reference voltage out of the PCM to make sure it`s powered up and workiing... You should have a 5 volt reference or signal voltage to your F/I.. emmission sensors. (I usually use the throttle position sensor) There are three wires.. one of them sould have 5 vlts with the key on.

neon_boy82 · 11-04-2007, 06:21 PM

okay all of the connections from the pcm were checked and they all had good voltage. He also repaced the fusible links and it still isn't working. Any new ideas?

nnunez · 11-05-2007, 11:45 AM

If you jumped the fuse and the fuel pump worked, then it could be the relay......
but why wouldnt the idiot lights work? They are not the same circuit?

Whatever it is, let us know when you find the solution.

neon_boy82 · 11-07-2007, 02:21 PM

okay so the problem turned out to be the ignition switch. There was nothing wrong with the pump or the lights. When the key was turned on, all you could do was move the gear selector. There wasn't any power going to anything else.

crabtruck · 11-07-2007, 04:15 PM

Thanks for posting back the results, glad to here it's fixed.
As often as the key is a problem causer, we should probably think of it more often.
Can't tell you the number of times my truck wouldn't start until I found the keys.

11-02-2007, 03:37 PM	#1
neon_boy82 Junior Member Join Date: Nov 2007 Posts: 4	help!!!1996 Blazer no dash lights or fuel pump Hi everyone. My neighbor has a 1996 4.3L Blazer and it won't start. When he turns the key it cranks but the fuel pump doesn't turn on and the only thing on the dash that works is the shift indicator lights, no check engine. battery, etc. If he jumps the eninge fuse in the panel to the one beside it the lights and the pump come on but it still won't start. Is it a shorted wire or a relay or what? Any help would be appreciated. Thanks.

11-02-2007, 04:00 PM	#2
scottie Senior Member Join Date: Jan 2006 Location: South Florida (Palm Beach), originally from south of BOSTON Posts: 644	go through the fuses (dont "jump" any fuses, it could damage something) and check for any blown ones... there is also an inertia switch, that i beleive is in the cargo compartment that could have opened the circuit if he slammed the door or kicked it (it happens beleive me). id say check all fuses(under dash and in engine bay) make sure they all work. __________________ im a straight shooter with upper management written all over me

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11-02-2007, 05:37 PM	#3
crabtruck Senior Member Join Date: Jul 2007 Location: on your 9 Posts: 3,364	Don't forget to check the fusible links to the junction block. What does work ? Blower, radio. turn sigs ? Welcome aboard.

11-02-2007, 06:38 PM	#4
neon_boy82 Junior Member Join Date: Nov 2007 Posts: 4	everything else works except the fuel pump and the idiot lights on the display. He doesn't have a repair manual so we couldn't find the fuse box or the fusible links under the hood. Also he said a couple days ago that it was taking a couple tries to start his truck so I'm guessing the pump wasn't coming on the first time.

11-02-2007, 07:30 PM	#5
tjzz4 Senior Member Join Date: Oct 2007 Posts: 277	I`d check ror reference voltage out of the PCM to make sure it`s powered up and workiing... You should have a 5 volt reference or signal voltage to your F/I.. emmission sensors. (I usually use the throttle position sensor) There are three wires.. one of them sould have 5 vlts with the key on.

11-04-2007, 06:21 PM	#6
neon_boy82 Junior Member Join Date: Nov 2007 Posts: 4	okay all of the connections from the pcm were checked and they all had good voltage. He also repaced the fusible links and it still isn't working. Any new ideas?

11-05-2007, 11:45 AM	#7
nnunez Senior Member Join Date: Dec 2005 Posts: 307	If you jumped the fuse and the fuel pump worked, then it could be the relay...... but why wouldnt the idiot lights work? They are not the same circuit? Whatever it is, let us know when you find the solution.

11-07-2007, 02:21 PM	#8
neon_boy82 Junior Member Join Date: Nov 2007 Posts: 4	okay so the problem turned out to be the ignition switch. There was nothing wrong with the pump or the lights. When the key was turned on, all you could do was move the gear selector. There wasn't any power going to anything else.

11-07-2007, 04:15 PM	#9
crabtruck Senior Member Join Date: Jul 2007 Location: on your 9 Posts: 3,364	Thanks for posting back the results, glad to here it's fixed. As often as the key is a problem causer, we should probably think of it more often. Can't tell you the number of times my truck wouldn't start until I found the keys.