Trouble Checking 84 SVO Codes

[diesel_farmer]

84 SVO. See attached photo showing the wiring. I also pasted the below photo of the Code diagram. I'm trying to successfully check codes. The two black wires go to pin #2 (I pulled them out of the plug to make sure I was getting good contact) and the yellow wire piggybacks the black wires to the STI (which is a white wire with red stripe - I'm pretty sure it's not the wire that runs to the hood light - and I had to put a new end on it because the old connector end was falling off). The tester is hooked to the positive battery terminal and lights up when grounded, so I know the tester works fine. When the ignition is turned on, the test light comes on for a second and then goes off - the test light does not go on and off showing any codes. If I try warming up the car and then testing, still no lights blinking to show codes. If I try checking codes with the engine running, still no light codes. Battery is new and alternator is charging at around 14.2 volts, so electrical system is getting a healthy feed. What am I doing incorrectly here? thanks for comments

http://www.svoca.com/FAQ/code.gif

[GAboySVO]

I would recommend spend the few dollars to get one of these.

https://www.autozone.com/test-scan-and-specialty-tools/code-reader/innova-ford-obd1-code-reader/273350_0_0?spps.s=963

[diesel_farmer]

GAboySVO -- Why do you recommend a code reader unit from autozone? If I can't get the test light to work, I don't see how the code reader will work, but maybe I'm amiss.

[GAboySVO]

Why do you recommend a code reader unit from autozone? If I can't get the test light to work, I don't see how the code reader will work, but maybe I'm amiss.

You don't have to guess which wire to test.

If you think you have a wiring issue, then you need to peel back all of the tape in the area to determine if the wire insulation has deteriorated and is causing a short. The 84 wiring looms are notorious for the insulation falling apart and causing electrical gremlins.

[diesel_farmer]

You don't have to guess which wire to test.

If you think you have a wiring issue, then you need to peel back all of the tape in the area to determine if the wire insulation has deteriorated and is causing a short. The 84 wiring looms are notorious for the insulation falling apart and causing electrical gremlins.

Thanks for the comments and I see your point -- without a wiring diagram, which I need to get, I don't know if I'm testing the correct wires to read codes -- of course, the code reader might not work correctly either if the wiring has been altered in the past.

[svono50]

For the life of me, I can't seem to dig up a 'good' wiring diagram that shows the self-test output connector (STO) and input (STI) wire codes for any 84-86 model...must be trying to hard. So, in the absence of that, here is the wiring on my 86 for reference. The (3) STO wires are Tan w/Green stripe, Black w/White stripe and Yellow w/Black stripe, while the (1) STI wire is White w/Red stripe. The STI wire goes to Pin 48 on the EEC.

The diagrams show jumper the STI wire with the Black w/White stripe wire (same positions you show in your pic) and the Yellow w/Black stripe wire goes to one lead of the noid light, while the other end of the noid light goes to the battery (+) terminal. It appears your connections are correct, so long as the wires you have on the STO connector are correct. To initiate the test mode on the EEC, you first turn the ignition to RUN, then connect the STI jumper and watch the flashes. I don't think the self-test will initiate if the STI jumper is connected when you turn the ignition switch on. Not sure if this helps, but hopefully it does.

[SVOeric]

https://www.svoca.com/forum/showthread.php?15787-How-to-pull-codes-and-code-list

your test light is on the wrong wire, and I don't see your 'jumper' wire.. but there is some wire stuff there I don't know what is...


see above