Mobicool c40 dc - 2013 Chevrolet Tahoe

The best way to fix the problem is to getting help from service and repair manual with diagram which will provide you step by step help to locate and fix the problem on your own easily and you will get the manual from the given link https://toolsnyou.com/

how about this one
https://www.ebay.com.au/itm/48V-to-12V-30A-STEP-DOWN-DC-DC-CONVERTER-VOLTAGE-REDUCER-BULK-TRANSFORMER-MODULE-/322884507536
or
https://www.ebay.com.au/itm/48V-to-12V-20A-Voltage-Reducer-DC-DC-Converter-for-Golf-EZGO-20AMP-240W-AUS/322884503196?_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D2%26asc%3D20160323102634%26meid%3Dae4fd6948b50487fb8d6e57bb152e4e2%26pid%3D100623%26rk%3D3%26rkt%3D6%26mehot%3Dag%26sd%3D322884507536%26itm%3D322884503196%26pmt%3D0%26noa%3D1%26pg%3D2047675&_trksid=p2047675.c100623.m-1
or
https://enerdrive.com.au/product/en-dc4812-25g-battery-converter/

Hi Diego.
Chevrolet Wikipedia
Chevrolet Series 40 50 60 67

Fixed Switches Product Series Model AC and DC Power Module Mixing S3700/S5700/S6700 S3700-26C-HI Supported S5710-28C-EI Supported S5710-52C-EI Supported S5700-28C-HI Supported S5700-28C-HI-24S Supported S5700-EI (non-PoE) Supported in V200R005 S5700-SI (non-PoE) Supported in V200R005 S6700 Supported in V200R005 S5710-HI AC and DC power modules cannot be used together, but 350 W and 1150 W AC power modules can be used in one switch. S5720-HI Supported Modular Switches · When a switch does not use a PoE power module:
AC and DC power modules cannot be used together in the same type of power slots. Power modules with different power values cannot be used together either.
·
· When a switch uses a PoE power module:
Version PoE Power Module System Power Module V200R005C00 and earlier versions AC AC DC power module not supported - V200R006C00 and later versions AC AC DC DC AC DC ·
AC and DC power modules cannot be installed in the slots of the same type (system or PoE) in the same switch, and the power modules of different power values cannot be used in the same switch.
·


S5720 Switch Thunder link com

Dc stands for Direct current its a constant non varying current
the only disadvantage is it will now able to travel over a long distance
http://www.instructables.com/answers/Why-DC-current-is-not-used-in-Homes What Are the Uses of Direct Current eHow Why do we use Alternating Current AC instead of Direct Current DC in power...

check horn dc supply using 12 volt dc bulb, if there is proper dc supply, adjust horn's rear adjusting screw, otherwise replace the horn

clean and check switch

What about the DC/DC converter?

Well you need special tools to check fuel pressure. The filter, you will run into the same problem,tools. You're on the right track though,it probably is a fuel pressure problem. Another possible problem,based on it picks up & slows down is a clogged catalytic converter. Ask back if this doesn't help.

The alternator.
It should produce 13.5-14.6 volts DC when charging a 12V battery