I've studied the wiring diagram of the ECU. I am trying to find the wire which causes the upshift light to come on, on an HF.
I just made an OBD0 to OBD1 adapter and while I have it appart I'd like to tie into that wire for a stealth shift light.

also,
Does the 90-91 HF have an upshift light? Is it only on the HF?

Thanks

 

yeah its only on the Hfs... but for somereason mines didnt work...i would tap out first and second at 5500 rpm and nothing would go on....im not so sure what wire it is though

 

im not so sure that the stock one was all that accurate. on my hf with the stock motor it seemed i had plenty of more rpms to travel and it was like SHIFT!

 

did all of the HF's have this? my buddy has an 88 HF, and i've never seen an upshift light on his.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mr_CRX &raquo;</TD></TR><TR><TD CLASS="quote">did all of the HF's have this? my buddy has an 88 HF, and i've never seen an upshift light on his.</TD></TR></TABLE>

all hf's have this option except for models for our beautiful california. my 88 HF came from washington so i have this on my HF. also this shift light is on the ecu itself. i had a PM6 and now a PG7 ecu and the shiftlight wouldn't work anymore but it works on my PM8(hf) ecu.

 

I believe that you'll find the "shift" light does not have a direct link to the ECU. I wanted to use the shift light on my HF's Cluster Gauge for showing when VTEC is active on my JDM D15B... If you remove your cluster, there will be a small white box on the center backside... that is what controls the shift light. I attempted wiring it up to use the light to no avail so I just cut the wires for the light itself and ran a wire to the ECU myself (tapped into VTEC switch wire that gives +12v when VTEC is active) and ran the correct ground wire to one of the grounds on the back of the cluster. I looked through the Helms on the cluster and couldn't find a way around doing this because the little white box has a number of components inside that determine the shift light's activation point.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Origin &raquo;</TD></TR><TR><TD CLASS="quote">im not so sure that the stock one was all that accurate. on my hf with the stock motor it seemed i had plenty of more rpms to travel and it was like SHIFT! </TD></TR></TABLE>

I'm pretty sure it was just there to indicate the best time to shift to get the best fuel mileage. my buddy has an HF and the light does come on early. Also(sorry this is nothing about the light) his 3rd gear was funny. it was really long.

 

The second question should read;

Does the 90-91 HF have a shift light?

I have seen 88 and 89 clusters and the HF has them. I was just wondering because I want to make a hybrid 90-91 cluster that has the big tach, 150mph speedo and a shift light that I will trigger with an RPM switch.

I know the power for the light comes from the dimmer switch. I took mine out and the light stopped working. Its really odd. I used to hate that light, always coming on at 1700 rpm but once it quit working I actually missed it. It seems to be RPM, load and throttle position sensitive.

The ECU must control it somehow because like the guy above said, when he changed ECUs the light stopped working. I bought a Civic book. I guess I'll start tracing the wiring.

Thanks for the effort