Gage/idle fuse blows when key on

[454-k10]

Hello everyone. Need help. I have a 1985 k20, sbc. Custom deluxe. When I turn key on gage/idle fuse blows. Only Speedo works. No other gauges work. Tank selector and fuel gauge also don’t work. Removed fuel tank selector switch and pink wire from tank selector switch from fuse block and also gauge cluster removed (dash lights still work). I’m at a lose. Original carb gone, it has an Edelbrock 1406. But all the “ecm” or whatever they are on the 85 models are still intake and connected. Truck only has 70k original miles. Everything was perfect until one morning when the gauges stopped working. Any help would be great. Thanks

 

[Broken85]

This is for an 84 and it says you need to trace the pink wire, but I believe the wire coming out of the back of the fuse box is a pink with a black stripe. It goes to the gauges first then feeds the switch valve circuit. The short must be between the fuse block and the gauge cluster.

 

[Ricko1966]

https://www.gmsquarebody.com/threads/89-suburban-5-7-blowing-fuse-5-gage-idle.45425/

 

[454-k10]

https://www.gmsquarebody.com/threads/89-suburban-5-7-blowing-fuse-5-gage-idle.45425/

Interesting. Thank you.

 

[Ricko1966]

Interesting. Thank you.

There's more links in that thread check those too.

 

[Jgonick]

yep- pink/black wire that goes to a lot of things. I'm currently chasing down the same problem (mine is random and doesn't happen often- which makes it difficult to find). I've traced mine down to the convenience center so far.


download the wiring diagram -link-

 

[454-k10]

It’s definitely a frustrating issue. I’ve owned many squares and never encountered this problem. I’m hopeful I can locate it soon. I drive my K20. I don’t like putting miles on my L5P and the K20 is much more fun to drive.

 

[Jgonick]

Tank selector and fuel gauge also don’t work. Removed fuel tank selector switch and pink wire from tank selector switch from fuse block and also gauge cluster removed (dash lights still work).

Explain this to me a little better. Did the tank selector stop working at the same time as the blown gage/idle fuse or is it two separate problems? The fuel gauge not working makes sense because it is fed by pink/blk wire from gage/idle fuse. Also what do you mean gauge cluster removed- if you unplugged the cluster the dash lights shouldn't work- if you did unplug the whole instrument cluster- Did the fuse still blow?

i am assuming original wiring and not aftermarket gauge/instr cluster.

 

[454-k10]

Explain this to me a little better. Did the tank selector stop working at the same time as the blown gage/idle fuse or is it two separate problems? The fuel gauge not working makes sense because it is fed by pink/blk wire from gage/idle fuse. Also what do you mean gauge cluster removed- if you unplugged the cluster the dash lights shouldn't work- if you did unplug the whole instrument cluster- Did the fuse still blow?

i am assuming original wiring and not aftermarket gauge/instr cluster.

Ok, so the tank selector switch did stop functioning. My right tank was almost empty but when the other gauges quit working the fuel gauge read half and i actually ran out of fuel. Tank selector didn’t work. I had switched the tanks on the switch and when I installed a new fuse the switch was able to function enough to change tanks even though the fuse blew immediately but the truck started finally and I got home. The gauges themselves stopped functioning but the lights in the cluster worked. I unplugged the connector in the back of the cluster and the fuse still blew. All original wiring. “Removing” the cluster meant i actually unplugged and then pulled it from the dash (not necessarily relevant but that’s what I meant so everyone knew it wasn’t the issue). I did more research and found the choke and tcc were on the same circuit. It ended up being the tcc. I unplugged it and the fuse hasn’t blown. So I’m assuming somewhere the insulation has rubbed off and grounded/shorted. It’s a one orange wire tcc on a TH400. I read I don’t need the tcc to safely drive the truck so I’ll leave it unplugged while I investigate further and locate the problem. I’m in the process of reinstalling the dash now and putting the truck back together. Just happy I’ll be able to drive my truck again.

Thank you everyone for the help and info. Hopefully someone in the future will benefit from this.

 

[gmbellew]

Ok, so the tank selector switch did stop functioning. My right tank was almost empty but when the other gauges quit working the fuel gauge read half and i actually ran out of fuel. Tank selector didn’t work. I had switched the tanks on the switch and when I installed a new fuse the switch was able to function enough to change tanks even though the fuse blew immediately but the truck started finally and I got home. The gauges themselves stopped functioning but the lights in the cluster worked. I unplugged the connector in the back of the cluster and the fuse still blew. All original wiring. “Removing” the cluster meant i actually unplugged and then pulled it from the dash (not necessarily relevant but that’s what I meant so everyone knew it wasn’t the issue). I did more research and found the choke and tcc were on the same circuit. It ended up being the tcc. I unplugged it and the fuse hasn’t blown. So I’m assuming somewhere the insulation has rubbed off and grounded/shorted. It’s a one orange wire tcc on a TH400. I read I don’t need the tcc to safely drive the truck so I’ll leave it unplugged while I investigate further and locate the problem. I’m in the process of reinstalling the dash now and putting the truck back together. Just happy I’ll be able to drive my truck again.

Thank you everyone for the help and info. Hopefully someone in the future will benefit from this.

almost the exact same situation as my 1990 in the linked post above. look for a. area where that wire is held in place by a bracket by the transmission. that ks where it was on my 1990. look at night with a flash light. the rub through will be shiny and reflective wire