Working on adding a head unit to my 87’ Iroc. I’m getting misleading info on what harness I need.

Crutchfield said I need Metra 70-1677-1, however my plugs appear different and look much more like they’d fit 70-1858. 3 individual plugs white black and blue.

Any input, not finding many similar threads with this same plug combo.

 

I used 70-1858, same setup as yours.

 

Those are the 89-later style plugs that would use the 1858 harness. But if the car is 1987, then the plugs should be different and would fit the 1677 harness. The only thing I thought might make a difference would be a Bose system, but a picture of a 1987 Camaro Bose radio shows connections that are consistent with 1987. What radio was in the car? I'm wondering if the harness in there was changed to fit a newer radio. Have you dug back in there to see if that harness looks original to the car?

Edit: Since you're looking for a conversion harness, I'd guess you're looking at an aftermarket radio. But as it is, you're not limited to an earlier style OE radio, so if you're going for an OE style radio, then you can plug-and-play anything from 89-92, such as a factory CD radio. Even a 93-02 4thgen radio will plug in too, although its mounting flanges will be slightly different.

 

I'm looking to just put a newer single din headunit in. Something with USB charge and bluetooth streaming. The wires are taped up very nicely and together in the dash, that's why I believed it to be factory. But I guess its possible someone at some point swapped new plugs in. I will just go with the Metra 1858 harness. Thanks.

 

Your 89 *should* have the early 'large plug' Radio harness. You should take a quick look to see if the later plugs were cut spliced. I can see someone used a zip tie - so the previous owner probably just cut/spliced the later harness on so that he matched whatever working factory that he got his hands on.

Hear me out here, -------------> You ( probably) already have a set of cut spliced radio plugs. Your going to spend $$ just too install a plug and another splice to each and every wire to the radio. Why not cut the current radio plugs from the dash harness and splice the radio directly to the dash harness. It would save you the time/expense of the plug and reduce the amount of splices too all the radio wiring by 50%. Just save the factory plugs you cut off and keep them in your toolbox in case you ever want to reinstall as factory radio. ( in that instance you'll probably want to install the PROPER 82-88 radio plugs anyway ! )

Just my 4:49 AM !


Edit: Radio Wiring Diagram :

 

I agree with you. Now looking at it further under the yellow electrical tape is probably splices from the add on. If they are not too far back under the dash, it def. would be easier doing it that way.