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Wiring a radio

1998 GMC sonoma ext. cab. New radio, looked up wiring diagrams for it but when i remove the old radio it had 2 plugs instead of one and many wires of the same color. Can anyone shed light on this situation? I know I have to cut the existing plugs off but what of the extra wires?

First. Never cut or splice radio wires on a vehicle with computers. You need a kit that adapts your factory wiring to the radio. If you don’t you could be in for some major problems. Cutting and splicing in radios went out the window about 30 years ago.

You might call Crutchfield, they send the correct adapter kits with the radios they sell, they may be willing to sell you the adapter cable separately. It plugs into the GMC’s wiring without cutting any of the truck’s wires.

+1 on Crutchfield.
No muss, no fuss.

Here’s a third person who recommends Crutchfield. If you haven’t bought a radio yet…check them out. When you buy a radio from them…the wiring harness and possibly bracket for your exact vehicle comes with the radio. You just plug everything in and it works perfectly.

If you already bought it (not from crutchfield)…the install kits are still available. I think a wiring harness costs about $30 for most vehicles.

Plus the folks at Crutchfield can tell you which wires you can safely ignore and what is essential.

One plug is for the actual radio functions (power, ground, accessory, speakers) and the other–depending on the trim level of your truck and what kind of OEM radio you have–is for a possible OEM external tape player, CD changer, steering wheel controls, or even OnStar. In any case, just purchase the correct wiring harness (Metra’s is part# 70-1858) and wire it to the aftermarket radio’s harness and plug it into whichever plug in the dash it fits onto. The other plug you can just leave alone.
But, as the others have said, do not cut anything–unless you’re skilled with a digital multimeter :slight_smile: