s10 blowing #4 fuse (guages)

[vaughnj]

I started with a small problem. When I press on the horn, the interior lights come on and a faint noise from the horn can be heard. When I push in the cigarette lighter, the interior lights come on. I ran this way for a while. Soon the #4 guages fuse blew. I took out the alternator and had it checked. It was fine (supposedly). The #4 fuse blew again and now it blows as soon as I turn on the ignition. If I start the truck and disconnect the positive battery cable, the engine dies. Could it still be the alternator shorting out?

[OverBoardProject]

newer cars need a battery to run with all the electronic's. Removing the positive battery terminal while the engin runs could cause an electric surge and burn out the electronics.

What you have is a short somewhere.

The good news is that they are usually cheap to fix, (if you do the work yourself) the bad news is that they are hard to find.

You'll have to trace all the wires leaving the #4 fuse to the source looking for any bare wires. I would start towards the horn since it's probably the easiest to trace, and the steering columb is where so many electric problems start.

It might be easiest to just disconnect the horn from the fues box then try a new fuse. If it still blows hook the horn back up, then remove the next wire.. and so on and so on

Good luck and when you get to stressed out take a break or call it quits for the day

[BlazerLT]

Originally Posted by vaughnj

I started with a small problem. When I press on the horn, the interior lights come on and a faint noise from the horn can be heard. When I push in the cigarette lighter, the interior lights come on. I ran this way for a while. Soon the #4 guages fuse blew. I took out the alternator and had it checked. It was fine (supposedly). The #4 fuse blew again and now it blows as soon as I turn on the ignition. If I start the truck and disconnect the positive battery cable, the engine dies. Could it still be the alternator shorting out?

I would check your fuse panel for some of the connections being loose on the back side of it.

Also, don't remove the positive cable when running unless you want to take the chance of blowing your computer.

[vaughnj]

I ran down what I could under the dash. After I put it back together, everything seemed fine except the speedometer. It was still pegged out. The tach was fine. The fuse was fine. The alternator was charging. When I started down the road, the speedometer move slightly and the fuse blew again.

[OverBoardProject]

your on the right track then. Try disconecting the speedo and see what happenes.

That's all the pros do except they have some fancy meters that help them find some problems

[vaughnj]

I can remove the digital instrument cluster from over the steering wheel. But, How do I disconnect the speedometer. Do you mean the vss?

[OverBoardProject]

I wish that I could tell you but without a book in front of me I can't.

Look in a shop type manual and it'll tell you everything. If you don't own one look in the library

[cmr29sun]

Amen... Finally. ..I have read every electrial problem post on this forum and was putting off having to post mine but now this is it. I have the exact same problem. Started with same wierd things horn controling interior light ect. That seemed to be fixed for months and then #4 blew and nothings been the same since. Alt. also bench tested fine. We did replace the ignition switch I believe not sure prior to #4 blowing. My theroy has been it had to of been something "we" did that changed the condition of the truck.Tried even putting a second ignition switch in. I was thinking it has to be in that dang column. The left turn signal does not go off by itself but that isn't on that fuse so I assume unrelated. The speedometer has always been moody sometimes requiring a little tap on the gauge board to get it unstuck been that way for years. We have also been physically been over nearly every inch of wire inside and engine comp. and no obvious problems there. We have taken off bracket on column and dropped it then wiggled. examed everything under there. We then try a new #4 fuse and it will work fine for 10 mins , a mile , 100 feet...never seems to blow under same circumstances. Turn off truck try just popping in another right after it blows and you can only get as far as turning the key to the off unlocked position and pop #4 blows. I was begining to think it has to be something we are resetting or what not that makes it do the run a bit then blow before even a start. As for it being the gauges meaning something in the gauge board it self well we have removed that completely and the fuse still blows. That doesn't eliminate wiring up to the conection plug for the gauges but like I said nothing obvious but I am certainly no electrician. I can't afford to take it to the shop and in fact when I had the loot saved to bring it in the radiator cracked and I had to deal with that first. I will tell you I am a 37yr old mommy to a 4 yr old and hubby not so mechanically inclined or does he find it a hobby he wants. Which is fine with me I have learned and really liked doing it myself including removal of radiator and replacing it, replaced starter (had hubby under there with me..lol) figuring how to get it out by reading this forum(backout the motor mount bolt a few threads and makes the impossible piece of cake.) I have read so much it would make your head spin. It does mine. Now even if I had all the money in the world no way this thing gets done by the shop especially after the radiator cracking day before it would of went to shop. That just pissed me off and I'm to stubborn. This electrical short has become lifes greatest mystery here...lol. and if I died and went to heaven tomorrow where was the damn short would be my first question I asked when I got there. Sorry to turn this into a book but it has been months of taking battery in and out to charge up so I can get to the grocery store or drive kid the mile to school when it rains. So please someone help this guy...help me ...If you need anymore info feel free to ask. I have gotten to know this freaking truck quite well to say the least. I have even been to library and photo copied every wiring diagram for it so ask away..post here or email me at christineconcann@hotmail.com if you like. My truck is a 94 s10 4x4 autotrans with the Zvin. Again sorry so long and to the guy that started this post thank you ,thank you...and best of luck ....AND POST POST POST ..hate posts where someone fixes thier prob but doesn't take time to enlighten the rest of us with what they have learned.

CMR29SUN

[vaughnj]

I removed the instrument cluster along with dash covers. The cig lighter seemed to be involved as I can push it in and get interior lights but no hot cig lighter. I unplugged the lighter and put everything back. It ran awhile but blew #4 again. I took it apart again. Checked every wire I could. Put it back together again. I have had no problems since, except, the interior lights come on when I push in the cig lighter or honk the horn (which only give me a buss from the dash. Probably the relay). When the driver door is open, the problem does not exist. I'm lost on this problem. I'm just gonna keep on truckin' til it happens again.

[16th hippy]

if the lights come on when horn is honked, or lighter is used, sounds like a faulty ground. The lighter is all metal that conducts electricity VERY well....and could be a good ground. wiring diagrams and schematics of ALL grounds on the truck would be good, and check EVERY one, visual and with a meter. hope this advice helps.

[matt17]

there is a service bullitin on this exact prob. it has to do with the horn,gm offers a kit to fix this,i can't remember the specifics but ill look them up and repost for you guys!

[matt17]

here is what i found(hope this helps)

Select Vehicle | New TSBs | Technician's Reference Component Search:



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1993 Chevy Truck S10/T10 Blazer 4WD V6-262 4.3L VIN W CPI
Vehicle Level Instrument Panel, Gauges and Warning Indicators Technical Service Bulletins All Technical Service Bulletins Digital Cluster - Blank, Speedometer at 188 W/Horn On


Digital Cluster - Blank, Speedometer at 188 W/Horn On
Notes

BULLETIN NUMBER: 93-8C-81

SECTION: 8C Instrument Panel

NUMBER: 4

CORPORATE
REFERENCE NUMBER: 368301

DATE: May 1993

SUBJECT:
DIGITAL CLUSTER GOES BLANK OR SPEEDOMETER READS 188 WHEN HORN IS DEPRESSED (INSTALL HORN KIT)

MODELS:
1993 S/T WITH DIGITAL IP CLUSTER (RPO U52)

CONDITION
Some 1993 S/T trucks with RPO U52 Digital IP Clusters may experience an intermittent blank IP cluster or a reading of 188 on the speedometer display when the ignition is on and the horn is depressed.

CAUSE
This condition is caused by a voltage spike in the horn circuit when the horn is actuated.

CORRECTION
To correct this condition engineering has released two service horn kits that have built-in electrical suppression. Vehicles have been corrected in production after the following VIN's:

Pontiac West P0513648
Moraine P2523127
Shreveport P8519090

SERVICE PROCEDURE

1. Disconnect and remove "F" note horn from the left radiator support.

2. Assemble "F" note horn and bracket from Horn Kit (P/N 10456443).

3. Install and connect the horn.

4. Disconnect and remove "A" note horn from the left inner fender.

a. T-Truck - Remove the oil filter. If equipped with an L35 engine, remove the air cleaner assembly.


5. Assemble "A" note horn and bracket from Horn Kit (P/N 10456328).

6. Install and connect the horn.

7. Reinstall the oil filter and remote air cleaner, if necessary.

8. Check and add oil as required.


SERVICE PARTS INFORMATION

Part Number Description Qty
10456328 Horn Kit "A" Note 1
10456443 Horn Kit "F" Note 1

Parts are currently available from GMSPO.







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