Mystery Wire Identification Help Please! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

badpeanut · 11-29-2003, 10:26 PM

I have a '71 Blazer with a 350/TH350. On the driver's side firewall there are two small electrical boxes. One is disconnected, and there is a rats nest of wires which I also can't identify. Can someone identify this stuff? Can I remove the remaining wires?

badpeanut · 11-29-2003, 10:28 PM

Mystery box #1 (this one is still hooked up):

badpeanut · 11-29-2003, 10:29 PM

Mystery box #2 (this one is disconnected):

badpeanut · 11-29-2003, 10:29 PM

Mystery plug #1:

badpeanut · 11-29-2003, 10:31 PM

Mystery plug #2:

krue · 11-30-2003, 12:16 AM

Mystery box #2 looks like a blower motor relay. Do you have a factory ac truck? Mine is mounted on the pass. side of the engine firewall beside the vacuum can.

JimKshortstep4x4 · 11-30-2003, 01:08 AM

It looks like the relays and plugs are part of the TCS system, (Transmission Controlled Spark). The TCS system is set up to control the vacuum advance and will not allow the advance to function unless the transmission is in high gear and the engine is warmed up. The engine should have had a temperature sensor in the right side head and there would have been an electrically controlled vacuum switch on the manifold. The vacuum line running to the vacuum advance would have been interrupted by the switch. The number 1 plug shown was plugged into the transmission and the number 2 plug was for power for the system. The relays shown were for controlling the vacuum switch, one for the transmission and one for the temperature signal.

The engine will run better and get better gas mileage without the system in place. The emission system appears do little to reduce emissions and many suspect it actually increased emissions.

Jim

badpeanut · 11-30-2003, 02:52 AM

Thanks for the replies! Sounds like I can ditch the stuff. It is a non-AC truck. The engine is not original, the heads are earlier castings, and it has an aftermarket aluminum intake so none of the TSC stuff is actually left.

BobbyK · 11-30-2003, 03:25 AM

JimK is exactly right,TCS stuff.
My carb is long gone,TPI now.I removed all that wiring without any problems.

11-29-2003, 10:29 PM	#3
badpeanut Not a bad nut after all.. Join Date: Dec 2000 Location: ND Posts: 1,756	Mystery box #2 (this one is disconnected): Attached Images

11-29-2003, 10:29 PM	#4
badpeanut Not a bad nut after all.. Join Date: Dec 2000 Location: ND Posts: 1,756	Mystery plug #1: Attached Images

11-29-2003, 10:31 PM	#5
badpeanut Not a bad nut after all.. Join Date: Dec 2000 Location: ND Posts: 1,756	Mystery plug #2: Attached Images

11-30-2003, 12:16 AM	#6
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,450	Mystery box #2 looks like a blower motor relay. Do you have a factory ac truck? Mine is mounted on the pass. side of the engine firewall beside the vacuum can. __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

11-30-2003, 03:25 AM	#9
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,771	JimK is exactly right,TCS stuff. My carb is long gone,TPI now.I removed all that wiring without any problems. __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE

11-29-2003, 10:26 PM	#1
badpeanut Not a bad nut after all.. Join Date: Dec 2000 Location: ND Posts: 1,756	Mystery Wire Identification Help Please! I have a '71 Blazer with a 350/TH350. On the driver's side firewall there are two small electrical boxes. One is disconnected, and there is a rats nest of wires which I also can't identify. Can someone identify this stuff? Can I remove the remaining wires? Attached Images Last edited by badpeanut; 11-29-2003 at 10:33 PM.

11-29-2003, 10:28 PM	#2
badpeanut Not a bad nut after all.. Join Date: Dec 2000 Location: ND Posts: 1,756	Mystery box #1 (this one is still hooked up): Attached Images

11-30-2003, 01:08 AM	#7
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	It looks like the relays and plugs are part of the TCS system, (Transmission Controlled Spark). The TCS system is set up to control the vacuum advance and will not allow the advance to function unless the transmission is in high gear and the engine is warmed up. The engine should have had a temperature sensor in the right side head and there would have been an electrically controlled vacuum switch on the manifold. The vacuum line running to the vacuum advance would have been interrupted by the switch. The number 1 plug shown was plugged into the transmission and the number 2 plug was for power for the system. The relays shown were for controlling the vacuum switch, one for the transmission and one for the temperature signal. The engine will run better and get better gas mileage without the system in place. The emission system appears do little to reduce emissions and many suspect it actually increased emissions. Jim

11-30-2003, 02:52 AM	#8
badpeanut Not a bad nut after all.. Join Date: Dec 2000 Location: ND Posts: 1,756	Thanks for the replies! Sounds like I can ditch the stuff. It is a non-AC truck. The engine is not original, the heads are earlier castings, and it has an aftermarket aluminum intake so none of the TSC stuff is actually left.



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