Front Park fuse #37 keeps blowing after LED switchback install

Zx2ner88

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Jan 2, 2013
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51
I just installed a pair of LED switchbacks for the front turn signals and now the rear fuse #37 keeps blowing out when the lights are turned on. I already had 2 194 LEDs installed in the corner lights and they always worked properly. After I put the switchbacks in, the 194s dont come on at all, and when I put the turn signals on, the switchbacks light up amber and white at the same time with no parking function. According to the seller the bulbs should be white for parking lights, then the white should go out and only the amber should flash for the turns. The fuse only blows if the headlights are turned on. Did I do something wrong here?
 
What year is your vehicle? If you have a 2002 or 2003, you might have SRCK sockets and putting conventional bulbs will cause issues like the ones you're having.

You may want to fill out your vehicle profile to help folks out assisting you down the road in future threads :twocents:
 
I believe so, could be pretty pricey though. Where did you get your switchbacks from? It may be more cost effective to either exchange them for SRCK ones, or return them and try to buy some SRCK ones elsewhere.
 
I can get a set of bulb sockets at a local junkyard for around $8, if there is another model vehicle that would fit and has the standard style socket. I'm pretty handy with splicing and soldering so that wouldnt be an issue.
 
:undecided: I think you're safe if you pull the sockets off an 04 or later.
 
try to break it down one light at a time. The only lights I had to get srck for were my stop lights in the back. My turn signals both the little and large bulb are standard. Same for the licence plate and interior dome lights. If anything try to hook the leds up to a battery or 12v power source off the vehicle and test them to make sure they are wired right and operational.

For your information this link will show you what polarity you should find on the trucks socket as well as the bulbs you purchased as long as the bulbs are not CK style like our stop lamps are: http://www.vleds.com/media/catalog/...fe127f42dca9de82fb58b1/3/1/3157_socket_10.jpg

If you should have CK style lights such as our stop lamps then this is the layout of the socket and bulb: http://www.vleds.com/media/catalog/...e127f42dca9de82fb58b1/3/1/3157ck_socket_9.jpg
 
kickass audio said:
try to break it down one light at a time. The only lights I had to get srck for were my stop lights in the back. My turn signals both the little and large bulb are standard. Same for the licence plate and interior dome lights. If anything try to hook the leds up to a battery or 12v power source off the vehicle and test them to make sure they are wired right and operational.

For your information this link will show you what polarity you should find on the trucks socket as well as the bulbs you purchased as long as the bulbs are not CK style like our stop lamps are: http://www.vleds.com/media/catalog/...fe127f42dca9de82fb58b1/3/1/3157_socket_10.jpg

If you should have CK style lights such as our stop lamps then this is the layout of the socket and bulb: http://www.vleds.com/media/catalog/...e127f42dca9de82fb58b1/3/1/3157ck_socket_9.jpg

The SRCK front sockets are a thing with the early model years, it's been confirmed by a number of other members with 02s when they put LEDs in the front turn signals. The tail lights are across the board though. :weird:
 
Blckshdw said:
The SRCK front sockets are a thing with the early model years, it's been confirmed by a number of other members with 02s when they put LEDs in the front turn signals. The tail lights are across the board though. :weird:

way to go GM. smfh. What is even the point in ck? friggin engineers sometimes I swear. Sorry about the misinformation. Either way I would check out the pinouts and make sure they are okay and if they turn out fine then you can just get switchback ck lights. Here is one from the guys I got all my led's from: 6K TYPE 2 DUAL COLOR CHANGING WHITE AMBER SWITCHBACK 42 HIGH POWER LED TURN SIGNAL BULBS 3157 CK TYPE BASE | 1 PAIR - SwitchBack LED - 3157 - 3157CK - 3156 LED - Bulb Number

I only had one problem with led's from them, one of their older model led's had a flickering effect to one bulb and eventually it died out for the high + side so I only had low but I replaced it and all the others are fine (other than one that doesn't want to stay in the socket for my dome light but that is the dome light that is the problem not bulb).

I am sure you know how to tap a wire and figure it out but try to remove the load resistor from the truck when you go to test the pinouts on the OEM plug just to take that out of the equation when you see if you have traditional or CK. one thing I learned is never trust GM, they do weird little things like this between models and they are a pain for it. :hissyfit:
 
Blckshdw said:
The SRCK front sockets are a thing with the early model years, it's been confirmed by a number of other members with 02s when they put LEDs in the front turn signals. The tail lights are across the board though. :weird:

I'm one! I'm just changing out the sockets with non-SRCK one's to be able to get "normal" switchbacks because when the lights aren't on, the front indicators don't work, but when the lights are on, they work perfectly normal. :crazy:
 
Just in case I can't find sockets from a trailblazer, does anyone know if there are any sockets from another vehicle that will fit
 
All of the GMT360/370/305s use the same sockets. So Bravada/Rainier/Envoy/9-7x will work as well. As far as other platforms, no idea on that one.
 
As previously said look at any of those lines for a replacement one. I really don't know any other vehicles that have the same size socket for the turn signals.
 
Are they definitely standard sockets and not the SRCK kind? if so I'll probably just order those
 
I'd chance it, if I needed them. Conventional sockets were used pretty much everywhere, compared to the SRCK ones. :twocents:
 
The sockets should be arriving tomorrow so I'll keep everyone posted on whether they work with LEDS or not
 
Looks like these sockets are the SRCK type as well. Same result, blows fuse 37 and white and amber flash at the same time
 
Do you have a test bench, or a 9V battery, so you can test the bulbs outside of the truck? Where did you get your bulbs from? Maybe the bulbs are the problem, and not your truck? :confused:
 
Put in the factory bulbs and try again. I'm thinking you either have an issue with the bulbs themselves, or have something hooked up incorrectly.
Have you tried rotating the bulb 180 degrees?
What happens with stock glass bulbs?
With new sockets vs old sockets?
and LED?
and led turned around in socket?
 
I checked continuity between all 3 pins and the internal tabs and I get the same result with both. I didn't bench test the bulbs however. Stock bulbs work as usual with either socket. Bulbs were put in both ways. As I said both white and amber come on for turns with no parking function
 
I'm leaning towards bad bulbs. Something in there is shorting out your parking light fuse, if the stock bulbs work fine in both sockets.
 
I'll test them out on my brake light sockets since I already modded them to work with standard bulbs
 
I am going to 2nd the LED bulbs. If regular bulbs work, it would lead us to believe a defective LED. Check the contact area of the LED base. Make sure nothing is crossed or bridging the gap between turn and running lights.
 
Is the resistor hooked in correctly? from turn signal into ground?
Not turn signal into parking light circuit?

Although, if that were the case, the symptom would be consistent.
 
The load resistor won't cause you to blow the fuse, just get hyper flash. I did it to mine before I put the resistor on and I just used the wire that turns on and off with the signal and the common ground on the same bulb socket to wire up my load resistors.

I really am thinking your led might be bad or something is being overlooked. After you replaced the socket did you use a DMM to test the tabs for polarity to see if its standard or CK? I would first do that and then test the led on a bench but for protection you might want to wire a fuse inline with one of the leads you test the bulb with to protect from frying the bulb.

The whole CK crap with these vehicles is bull. I have all LED but 2 of the running lights in my tail lights. The running light in the middle that does not get bright when I hit the brake had to be the regular glass bulb otherwise it wouldn't work. I tried a CK and standard bulb in that socket and the CK wouldn't light no matter which way I had it in the socket, the standard would blow the fuse for vehicle stop when I hit the brake and never had light for a second. When I put standard bulbs in the CK socket of my tail lights that is for running and stop lights, the running light would work but when I hit the brake it was when it blew the vehicle stop fuse and then I wouldn't have running and stop lights. :hissyfit: I really see no point in the CK bulb other than to have another dumbass idea from the genius engineers at GM.
 
kickass audio said:
I really see no point in the CK bulb other than to have another dumbass idea from the genius engineers at GM.

I agree with the sentiment, but they must have conspired with the idiots at Toyota...they have them on highlanders etc too.
 
Not sure if you have LEDs in the side marker lights, but it's worth taking a look at:
When I was installing my front lights I had to switch the switchbacks and the LED side marker bulbs around in the socket multiple times until they both behaved normally.
My right switchback was only flashing white and I couldn't figure out why; switching the side marker bulb around in it's socket fixed it somehow.

As far as blowing the fuse, I'm not sure why that's happening, the only time I blew #37 was when I put some non-CK bulbs in the front turn signals.
Maybe somehow you have one CK socket and one non-CK socket up there? Have you tested them to confirm they are both CK?
Otherwise it has to be a bad bulb or something. :confused:
 

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