Fuses-Wiring

When something electrical isn't working, the first thing to check is for power/ground, and to ensure that the fuse for that circuit isn't blown.

The most common fuses used in the automotive industry are blade type fuses, the ones used in the A/S vans are ATO(regular), Mini, and Maxi.  

Fusible links are fuses that consist of short pieces of wire with special insulation so that it doesn't melt.  They are usually less than 7inches long, 2 to 4 AWG sizes smaller than the protected wire and are usually used on high current applications like your alternator or to protect multiple circuits.  You can buy pre-made fusible links at your LAPS, some make their own using special wire from the LAPS, or double wrapping proper sized wire with heat shrink tubing.

Here is an example of where you would find a fusible link:  There is one located in the alternator circuit that ties into the starter on every Astro/Safari van.

Some applications will require a circuit breaker to be installed, for example charging an extra battery or installing a brake controller.  These act like fuses but can be reset either manually or automatically.  If you are installing one for a brake controller, make sure it's an automatic reset type.

Wiring Sizes and Type

Wiring rated for automotive use is ALWAYS stranded, resistant to oil/chemicals/acids, use high temp rated for engine compartment usage.  In general you want to only use copper wire, it should state on the package that it is 100% Copper, or Oxygen Free Copper, OFC or something like that.  Stay away from Aluminum and Copper Clad Aluminum(CCA), it's cheaper but doesn't conduct as well, overheats and corrodes quicker, and fails sooner.  You will often find these in wiring "kits" and sometimes it's hard to find the wire type in the description.

You can use cross-linked polyethylene to replace PVC, but do not use PVC to replace cross-linked polyethylene.  Cross-linked polyethylene is never to be used where contact with fuels is possible.

• GPT/Primary/Trailer wire

A good general automotive wire commonly found at your LAPS. Multi stranded core and flexible PVC insulation usually rated to 80ºC (176ºF). Although some, TWP is rated to 105ºC (221ºF). It is resistant to oil, chemicals and acids.  Trailer wire is usually GPT with traditional color codes.

• 1015/Hook-up/Motor wire

Rated for higher voltages(600v) due to more/finer strands and a temperature rating of 105ºC (221ºF). It is resistant to grease, oil, acids, water, solvents, fungus.  Most commonly used as internal wiring in appliances and HVAC equipment, motor wire is finding increasing use in automotive applications. 

• SXL/GXL/TXL wire

SXL/GXL/TXL has a cross linked polyethylene jacket.  Rated for higher heat, abrasion, and ages better than than GPT wire.  GXL and TXL wire have thinner walled insulation. 

• Speaker wire

Paired stranded low voltage wire, with marked polarity, NEVER for carrying a load.

• Battery Cable

Battery cable is a larger heavier wire used to connect the battery to the fuse box, body ground, the starter, sometimes alternator(upgraded alternators). Susceptible to corrosion, often from the inside where you can't see it.  Can cause starting issues, a heavily loaded voltage drop test is the best for battery cables.

Wiring sizes in the diagrams are either listed in AWG or mm2, here are some conversions:

Metric(mm2) AWG

0.22 24

0.35 22

0.5 20

0.8 18

1.0 16

2.0 14

3.0 12

5.0 10

8.0 8

13.0 6

19.0 4

32.0 2

50.0 1/0