Hey guys, I bought one of the Technics branded cassette decks that was a premium option on the 87-88 Pickups to go into my 1985 SR5. Mine still has the factory cassette that came with that year and the original wiring/harness is still intact when I looked back there. So far I've noticed a couple of issues that I'm assuming I need to workaround to get the new deck in.

1. I could only find one plug going to radio, and I've noticed some over the 87+ models had a separate 2nd smaller plug that would go into the unit. Am I missing the factory amplifier or is it hiding somewhere in the truck? I don't have rear speakers, so would a newer unit run correctly without the amp plug connected?

2. I have the older radio connection type (wide, curved corners) so I was thinking of buying a spare newer harness and older harness off eBay to make a conversion cable. There's no problem in doing this is there? If I find the amp plug, I'm assuming I'd have to do the same for that harness connection as well.

I'm sure I'm missing something but if anyone has done this before, any help would be much appreciated.

Thanks!

 

1. The smaller harness (at least for the newer harness) is just for the rear speakers. I put one of those Technics cassette decks in my truck and I just have the smaller harness plugged into the back of the deck for later if I want to add rear speakers. Right now, I do not have any of the wires in the smaller harness connected to anything. The older style of connectors also had a smaller harness available but I am unsure what wires went to what. There is no separate audio amplifier for these decks.

2. Yes, you can convert to the newer style connector. The wiring positions in the connectors are probably different.

This diagram may help, but I am not sure how accurate this. The 1987 and newer part should be right. I am not so sure about the 1983-1986 part..... Definitely trace out what wire is what before splicing to make sure every wire connects to where it needs to go.

 

This is great, exactly the info I was looking for!

I went ahead and bought these two to make a conversion harness:

https://imgur.com/ar70uGr

https://imgur.com/d5H8Ure

The wires are labeled so hopefully it makes it easier to figure out what goes where.

 

Finished wiring up my conversion harness, except there's one issue I have. On the new harness side, I have an extra yellow wire for the battery backup 12v constant. For some reason the older style harness is missing that yellow wire.

Where should I attach that yellow wire? Do I splice it to the blue 'power/antenna' wire?

See below:

https://imgur.com/htp1JJw

 

Okay, after removing the old harness, I'm totally stumped. My SR5 has that small rare rear-single speaker and I think that's why my wiring looks so different.

I'm really trying not to hack up my old harness at all.

Behind Radio:

https://imgur.com/TWpxOuX

Radio Harness:

https://imgur.com/o0WFJgg

 

Well....

You got me stumped.

I forgot about the pretty rare optional "Woofer" rear speaker. I have yet to see one in person, just pictures I found here. According to the wiring diagram, there is a woofer speaker amplifier. I am not sure if it is built into the speaker housing, built into the radio, or is separate.

Here is a part of the 1985 radio wiring diagram I found, I hope it helps.

 

When I out mine in i bought it from cruthcfield and it came with a plug and play harness adapter. Maybe call them and see if you can buy the adapter?