50A IGN Starter SW/ Starter fuse blows every time I start the vehicle

Something that fuse powers is shorted to ground . Need to look at wiring diagrams , service repair manual , power distribution diagrams , disconnect everything it powers - one circuit at a time till fuse doesn't blow any more . Then find the short , videos on youtube showing how . EGN A ???? IGN A fuse . ENG 1 or 2
Underhood Fuse-Relay Center Fuse/Circuit Breaker
Rating
Description
ABS Fuse M4-N4
60A
Electronic Brake Control Module
A/C Fuse K11-L12
10A
A/C Compressor Clutch Relay
AUX A Fuse P7-R7
30A
Upfitter Provisions
AUX B Fuse P8-R8
30A
Upfitter Provisions
BATT Fuse M7-N7
50A
Instrument Panel Fuse Block
BLOWER Fuse M3-N3
60A
Blower Motor, IP Fuse Block
ECM-B Fuse F11-G12
20A
Fuel Pump Relay, VCM, PCM, Fuel Pump and Engine Oil Pressure Gauge Sensor
ECM-1 Fuse H7-J8
20A
Ignition Control Module, Ignition Coil, Camshaft Position Sensor, VCM, Fuel Injectors, Crankshaft Position Sensor
ENG-I Fuse L8-K7
20A
Heated Oxygen Sensors, Mass Air Flow Sensor, Exhaust Gas Recirculation Valve Solenoid, Evaporative Emission Cannister Purge Valve, VCM, Secondary Air Injection Relay, WATER IN FUEL Indicator Sensor, Fuel Heater, Glowplug Relay, Wastegate Solenoid, Crankshaft Position Sensor
HORN Fuse H11-J12
20A
Horn Relay, Underhood Lamp(s)
IGN Fuse F5-G6 (Diesel Only)
20A
PCM, Fuel Solenoid Driver, Engine Shutoff Solenoid
IGN-A Fuse M6-N6
40A
Starter Relay, Ignition Switch
IGN-B Fuse M5-N5
50A
Ignition Switch
IGN-E Fuse F7-G8
10A
A/C Compressor Clutch Relay
LIGHTING Fuse M8-N8
40A
Instrument Panel Fuse Block, Headlamp Switch
LH-HDLP Fuse F1-G2 (Export Only)
10A
Left Hand Low Beam Headlamp
LH-HIBM Fuse F3-G4 (Export Only)
10A
Left Hand High Beam Headlamp
RH-HDLP Fuse H1-J2 (Export Only)
10A
Right Hand Low Beam Headlamp
RH-HIBM Fuse H3-J4
10A
Right Hand High Beam Headlamp
RR BLOWER Fuse K5-L6
30A
Auxiliary Blower Motor Relays
ABS Relay (Expot Only)
--
ABS Warning Indicator Lamp
A/C Relay
--
A/C Compressor Clutch Coil
A. I. R. Relay
--
Air Ijection Reaction Pump Clutch Coil
Fuel Pump Relay
--
Fuel Pump
Horn Relay
--
Horns
Starter Relay
--
Starter Solenoid

What all does that fused supply B+ voltage too ? Do you know ? That would be your first thing to find out ! Do you know what a electrical distribution diagram is ? Do you know how to test electrical circuits with a DVOM - digital volt ohm meter ? Do you know what a short to ground is ?
Which fuse ? IGN A - 40 amp ,under hood fuse / relay box ? This fuse powers the Starter Relay and Ignition and Start Switch
Does your vehicle have a manual or automatic transmission ? The starter relay could be shorted inside , It's also located in the under hood fuse box . If you pull the relay out of the box it's plugged into an look on the bottom of it you would see four sets of numbers ! 30 & 87 an 85 & 86 . If you were to jump 30 to 87 in the relay box the starter should spin the engine over , not start an run just spin ! 85 & 86 is the control side . Could be the ignition switch !
That 40amp fuse powers a lot of subsystems !

Here is a web site for free diagrams !
http://www.bbbind.com/free_tsb.html Enter vehicle info. year , make , model an engine , Under system click on electrical distribution , under sub system click on power distribution . Then click the search button .Click blue links one at a time . First blue link scroll down to the second diagram . You will see Ign A 40 amp fuse at the top of the page .you will also see it powers the igintion switch ,look at last part of ignition switch , when in start or run that 40 amp fuse powers all those other fuse's plus three relays i see there also . A/C compressor relay , rear window defroster relay ,daytime running lights . Any one of those circuits could have your short . You need to isolate the circuits , pull fuse's till the fuse doesn't blow !

Is the 4th digit of your vehicle's VIN an "N"? If it is an "N", it looks like the IGN SW BATT 1 (fuse#5) powers up the powertrain control module (PCM), body control module (BCM), and instrument panel cluster (IPC). If your PCM ACC fuse G (10 amp) and IPC/BFC ACC fuse J (10 amp) in the left driver side fuse block in the dash are not blown, then you have a short circuit to ground in the wire between the IGN SW BATT 1 fuse in the underhood fuse block, and the ignition switch in the steering column. This would be a thick red wire. A short circuit to ground means that this wire somewhere has rubbed through and is touching metal. Find the short, repair the wire, and you'll stop replacing that expensive 40 amp fuse :)
Unless... someone has tapped into the wire (amplifier or stereo?) and is pulling way too much current through the wire, in which case the fuse would be blowing out. The correction for a blown fuse is NEVER to install a bigger fuse. You risk overheating the circuit and possible fire. Always find the cause of the short/overcurrent.

Power flows from Fuse 35 50A to IGN switch. Start by checking that fuse. From IGN switch to starter on black/white wire. Check for battery voltage on that wire at starter. If no voltage, check for voltage on black/white wire at IGN when turned to START. If no voltage, check for good power coming into the IGN switch on the the white wire from Fuse 35

( one question i have is every time the ignition fuse blows do i need to replace the starter relay? ) NO ! You have a dead short to ground on one of the circuits that fuse feeds. Do you know how to find a short circuit ? Video's on youtube show how. The fuse that blows ,is it IGN - A 40 amp. located in the under hood fuse/ relay center ? That fuse feeds B+ voltage to the ignition switch ,which powers up other thing's ,fuse's etc.. Not just the starter relay ! I see five other fuse's that get power from that fuse when ignition switch is in the start or run position . In the I/P fuse panel the gauges fuse #4 10amp , air bag fuse #10 10amp , turn b/u fuse #16 20amp. , Plus trans fuse #20 10 amp ! Pull out these fuse an try to start the van. if the ignition fuse doesn't blow the problem is in one of these other fuse circuits. There is one more fuse that get's B+ power from the ignition switch and ign A fuse ,crank fuse fuse #8 10amp. this powers the control side of the starter relay .
You can find a free wiring diagram here http://www.bbbind.com/free_tsb.html Enter vehicle info. year , make , model and engine . Under system click engine , under subsystem click starting. Click the search button then the blue link.
If you pull those fuse's i mention and it still blows the fuse look for a shorted ignition switch or wiring from ignition to the starter relay , not the relay itself. Park neutral safety switch . Isolate the circuit , pull the relay out of it's socket ,pull the crank fuse #8 in the I/P fuse box. with a ohm meter check to see if that part of the circuit is shorted to ground. Do you know how to do that ? Do you have a volt ohm meter ? You can buy one cheap at parts store .

The problem could be a shorted park netual safety switch . Do you know what a wiring diagram is ? It shows all the componets involved in a electrical circuit ! You IGN.1 fuse 40amp , GM calls it IGN A fuse 40 amp . It feeds the ignition switch and pin 30 at the starter enable relay .When you turn the key to the start position it sends B+ voltage to #8 crank fuse , located in the I/P fuse box ,from there it goes to the park netual safety switch , to pin 86 or 85 of the starter enable relay ! If you pull the relay out of the fuse box an look on the bottom you will see this four set's of numbers ,30,87 & 85 ,86 You can test at the fuse box where the relay plugs in . Here is a video on how to test . The guy presenting the video uses a horn circuit , but it works the same way . It happens a lot , the park netual safety switch shorting out . It may or may not be the problem . VEHICLE RELAYS Operation Diagnosis
Here is a web site for free wiring diagrams
http://www.bbbind.com/free_tsb.html Enter your vehicle info . then under system click on engine , then under subsystem click on starting . Then click on the search button an a link will pop up , click on it .You will see all the componets , connections , wiring colors etc... for the starter circuit for your vehicle .

load is measured in amps not ohms.ohms is a measure of resistance in a circuit.check the under side of the pdc for corroded wires or shorted wires on the load side of the circuit.

the neutral switch is located in the left side of the transmission and its connected to the shift cable.

what happens if the lights are on and he attempts to start? do lights dim or is there no change? If lights dim the ignition is making contact but the starter is not engaging ! If lights do not dim then the ignition is not making contact. start at the starter and check for ignition wire contact. a small 12 - 14 gauge wire. try to cross terminals on the selonoid and see if car will turn over, ( starter engage ) if it does then one of two things, selonoid is bad , or the ign wire is bad, some have a fusable link in-line check for one. you can check the ign wire by using a test light, ground to a good ground and while a helper turns key to start position test wire for power (test light lights ) if there is power then selonoid is most likely to be the culprit.Be sure to support car on jack stands or use two floor jacks or one floor jack and one bottle jack !!!! for safety reasons, of course if only one jack is used and it fails the possibilities of death is 98%, the possibilities of serious injury 100%. also keep fingers clear of all moving object in case something does engage causing movement.

Hi...
I read your problem.
Is there a few step to diagnostic or try to fix your car.

Follow this simple steps.
Inspect the RALAY " Starter relay # 47. or interchange with other one just for testing.
1- Check the Fuse " IGN E Fuse number 22 " 10amp. on under hood fuse BOX fron Neutro swicth
And power to the power to the Neutro safetly switch.
2-- Check the Fuse " CRANK fuse # 17 10amp. Under hood fuse box. 12v. from Ignition switch
3- check the fuse " IGN A fuse # 34 40 amp. under hodd fuse box. Constant 12v. to relay.
With ignition switch in ON position.
Crank Fuse only when you try to start. If no power 12v. come when trying to start.
REmove the steering column covers. to get axces to the IGNITION SWITCH.
Trying to start check if 12 v on the YELLOW wire exist. if not. Check if there a 12v on the RED wire
If not Inspect FUSE # 34.
But if there a power on the red wire But not ON yellow wire Trying to start.
Just REPLACE THE IGNITION SWITCH. Electrical part.

Check the NEUTRO SAFETLY SWITCH. connector under the car. Repair as need.
CHeck the BACK-UP lights, some times come damaged making a short on the Neutro safetly switch. ...

OK.. I hope this help on your problem.
If you need more information letme know.

I'm a Mechanic and have all the information for repair vehicles.

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